Develop Reference

What am I doing wrong with the below implementation for problem : queens-attack-2 hackerrank?

You will be given a square chess board with one queen and a number of obstacles placed on it. Determine how many squares the queen can attack.
Please find below my implementation.
Its working fine for many testcases but failing for few.
Am I missing any use case?
Kindly help. Thanks in advance.
import java.io.*;
import java.util.*;
import java.util.stream.*;
import static java.util.stream.Collectors.toList;
class Point{
int x;
int y;
public Point(int x, int y) {
super();
this.x = x;
this.y = y;
}
public Point() {
super();
}
#Override
public String toString() {
return "Point [x=" + x + ", y=" + y + "]";
}
}
class Result {
public static void printBoard(int n, int k, int r_q, int c_q, List<List<Integer>> obstacles) {
char[][] board = new char[n+1][n+1];
for(int i=0;i<=n;i++)for(int j=0;j<=n;j++)board[i][j]='.';
board[r_q][c_q]='Q';
for(List<Integer> o : obstacles) {
int x = o.get(0);
int y = o.get(1);
board[x][y]='X';
}
for(int i=n;i>=1;i--) {
for(int j=1;j<=n;j++) {
System.out.print(board[i][j]);
}
System.out.println();
}
}
/*
* n => row and column count in square board
* k => number of obstacles
* r_q => Queens row position
* c_q => Queens column position
* obstacles => All obstacles position in (row, column) format
*
*/
public static int queensAttack(int n, int k, int r_q, int c_q, List<List<Integer>> obstacles) {
// printBoard(n,k,r_q,c_q,obstacles);
/*
* Board is like below
* |
* ^ |
* | |
* | |
* | |
* row |
*index|
* |
* |_________________
* column index --->
*/
//initiate last available blank position for all 8 terminal points
Point
topLeft = r_q+c_q-1>n?new Point(n, r_q+c_q-n):new Point(r_q+c_q-1,1),
top = new Point(n,c_q),
topRight = r_q>c_q?new Point(n,n-(r_q-c_q)):new Point(n+(r_q-c_q),n),
left = new Point(r_q,1),
right = new Point(r_q,n),
bottomLeft = r_q>c_q?new Point(r_q-c_q+1,1):new Point(1,c_q-r_q+1),
bottom = new Point(1,c_q),
bottomRight = r_q+c_q-1>n?new Point(r_q+c_q-n,n):new Point(1,r_q+c_q-1);
for(List<Integer> o : obstacles) {
int x = o.get(0);
int y = o.get(1);
/*
* row==r_q would be horizontal line
* left and right would be needed to update
* if obstacle is at (2,3) and queen at (2,9)
* then last available space on left side is (2,4)
*
*/
if(x==r_q) {
if(y>=left.y && y<c_q) left.y=y+1;
if(y<=right.y && y>c_q) right.y=y-1;
}
/*
* col==c_q would be vertical line
* top and bottom would be needed to update
*/
if(y==c_q) {
if(x>=bottom.x && x<r_q) bottom.x=x+1;
if(x<=top.x && x>r_q)top.x=x-1;
}
/*
* row+col==r_q+c_q would be diagonal line from top left to bottom right
*/
if(x+y==r_q+c_q) {
if(y>=topLeft.y && y<c_q) {
topLeft.y=y+1;
topLeft.x=x-1;
}
if(y<=bottomRight.y && y>c_q) {
bottomRight.y=y-1;
bottomRight.x=x+1;
}
}
/*
* row-col==r_q-c_q would be diagonal line from top right to bottom left
*/
if(x-y==r_q-c_q) {
if(y>=bottomLeft.y && y<c_q) {
bottomLeft.y=y+1;
bottomLeft.x=x+1;
}
if(y<=topRight.y && y>c_q) {
topRight.y=y-1;
topLeft.x=x-1;
}
}
}
/*
* if in any line (x,y) is last available space and
* queen is at (r_q,c_q), then number of places queen can attack is
* |r_q-x| or |c_q-y| both would necessarily be equal
* so I am using any one of them
*/
return
(topLeft.x-r_q) +
(top.x-r_q) +
(topRight.x-r_q)+
(c_q-left.y)+
(right.y-c_q)+
(c_q-bottomLeft.y)+
(r_q-bottom.x)+
(r_q-bottomRight.x);
}
}
public class Solution {
public static void main(String[] args) throws IOException {
BufferedReader bufferedReader = new BufferedReader(new FileReader(new File("INPUT.txt")));
BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter("OUTPUT.txt"));
String[] firstMultipleInput = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");
int n = Integer.parseInt(firstMultipleInput[0]);
int k = Integer.parseInt(firstMultipleInput[1]);
String[] secondMultipleInput = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");
int r_q = Integer.parseInt(secondMultipleInput[0]);
int c_q = Integer.parseInt(secondMultipleInput[1]);
List<List<Integer>> obstacles = new ArrayList<>();
IntStream.range(0, k).forEach(i -> {
try {
obstacles.add(
Stream.of(bufferedReader.readLine().replaceAll("\\s+$", "").split(" "))
.map(Integer::parseInt)
.collect(toList())
);
} catch (IOException ex) {
throw new RuntimeException(ex);
}
});
int result = Result.queensAttack(n, k, r_q, c_q, obstacles);
bufferedWriter.write(String.valueOf(result));
bufferedWriter.newLine();
bufferedReader.close();
bufferedWriter.close();
}
}
Input file : https://drive.google.com/file/d/1yFPAIkW4o-Zf3fwf5o_qK-_ckZWLEAr0/view?usp=share_link
My Output : 190709
Expected Output : 110198

Not able to get 4 leading zeros in sha256 hash proof of work- ever (Java)

I'm build a blockchain app.
When I run tests in main, no matter what I do, no matter how much time I give it, when I log different things out, I'm unable to get 4 leading zeroes and so complete a difficulty level of 4. I see the log of the binary hashes and many times they have repeating elements, 1111 for instance, but never 0000 until my time is hit and the difficulty decreases to three. I have no idea why.
I borrowed the hash algorithm from an online source and I checked its output against an online hasher and it checked out.
I know with each level of difficulty it increases exponentially but 2^4 is still only 16 and I see other repeating numbers (1111, 1010, any combination except 0000). Is there any reason why this might be the case?
I wanted to provide an abundance of code rather than a shortage. Logically it makes no sense why randomly if all numbers were equally possible, it woudln't turn up 0000* (e.g. 0000101011at some point). therefore Four zeros must not be possible, but why? I waited 100 seconds mutliple times and saw other numbers repeat themselves. I saw it hit at exactly 4 or 3 or 2 seconds each time on the dot when difficulty went to three. When I start at difficulty 5 (genesis block) it will never solve- I'm sure even if I left it running overnight. So what could be going on?
package privblock.gerald.ryan;
import java.nio.charset.StandardCharsets;
import java.security.NoSuchAlgorithmException;
import java.time.Instant;
import java.util.Arrays;
import java.util.Date; // gets time in ms.
import privblock.gerald.ryan.util.CryptoHash;
/**
*
* #author Gerald Ryan Block Class of blockchain app
*
* Description: The block hash is the result of the timestamp, the
* last_hash, the data, the difficulty and the nonce
*
*/
public class Block {
long timestamp;
String lastHash;
String hash;
String[] data;
int difficulty;
int nonce;
// Millisecond basis
;
static long MILLISECONDS = 1;
static long SECONDS = 1000 * MILLISECONDS;
static long MINE_RATE = 2 * SECONDS;
/**
* A block is a unit of storage for a blockchain that supports a cryptocurrency.
*
* #param timestamp
* #param lastHash
* #param hash
* #param data
* #param difficulty
* #param nonce
*/
public Block(long timestamp, String lastHash, String hash, String[] data, int difficulty, int nonce) {
super();
this.timestamp = timestamp;
this.lastHash = lastHash;
this.hash = hash;
this.data = data;
this.difficulty = difficulty;
this.nonce = nonce;
}
public String toString() {
return "\n-----------BLOCK--------\ntimestamp: " + this.timestamp + "\nlastHash: " + this.lastHash + "\nhash: "
+ this.hash + "\ndifficulty: " + this.getDifficulty() + "\nNonce: " + this.nonce
+ "\n-----------------------\n";
}
/**
* Mine a block based on given last block and data until a block hash is found
* that meets the leading 0's Proof of Work requirement.
*
* #param last_block
* #param data
* #return
* #throws NoSuchAlgorithmException
*/
public static Block mine_block(Block last_block, String[] data) throws NoSuchAlgorithmException {
long timestamp = new Date().getTime();
String last_hash = last_block.getHash();
int difficulty = Block.adjust_difficulty(last_block, timestamp);
int nonce = 0;
String hash = CryptoHash.getSHA256(timestamp, last_block.getHash(), data, difficulty, nonce);
String proof_of_work = CryptoHash.n_len_string('0', difficulty);
// System.out.println("Proof of work " + proof_of_work);
String binary_hash = CryptoHash.hex_to_binary(hash);
// System.out.println("binary hash " + binary_hash);
String binary_hash_work_end = binary_hash.substring(0, difficulty);
// System.out.println("binary_Hash_work_end " + binary_hash_work_end);
System.out.println("Difficulty: " + difficulty);
while (!proof_of_work.equalsIgnoreCase(binary_hash_work_end)) {
// System.out.println("Working");
nonce += 1;
timestamp = new Date().getTime();
difficulty = Block.adjust_difficulty(last_block, timestamp);
hash = CryptoHash.getSHA256(timestamp, last_block.getHash(), data, difficulty, nonce);
proof_of_work = CryptoHash.n_len_string('0', difficulty);
binary_hash = CryptoHash.hex_to_binary(hash);
binary_hash_work_end = binary_hash.substring(0, difficulty);
// System.out.println(binary_hash_work_end);
// System.out.println(binary_hash);
// System.out.println(proof_of_work);
}
System.out.println("Solved at Difficulty: " + difficulty);
// System.out.println("Proof of work requirement " + proof_of_work);
// System.out.println("binary_Hash_work_end " + binary_hash_work_end);
// System.out.println("binary hash " + binary_hash);
System.out.println("BLOCK MINED");
return new Block(timestamp, last_hash, hash, data, difficulty, nonce);
}
/**
* Generate Genesis block
*
* #return
*/
public static Block genesis_block() {
long timestamp = 1;
String last_hash = "genesis_last_hash";
String hash = "genesis_hash";
String[] data = { "buy", "privcoin" };
int difficulty = 4;
int nonce = 0;
return new Block(timestamp, last_hash, hash, data, difficulty, nonce);
}
/**
* Calculate the adjusted difficulty according to the MINE_RATE. Increase the
* difficulty for quickly mined blocks. Decrease the difficulty for slowly mined
* blocks.
*
* #param last_block
* #param new_timestamp
*/
public static int adjust_difficulty(Block last_block, long new_timestamp) {
long time_diff = new_timestamp - last_block.getTimestamp();
// System.out.println(time_diff);
if (time_diff < MINE_RATE) {
// System.out.println("Increasing difficulty");
return last_block.getDifficulty() + 1;
} else if (last_block.getDifficulty() - 1 > 0) {
// System.out.println("Decreasing difficulty");
return last_block.getDifficulty() - 1;
} else {
return 1;
}
}
/**
* Validate block by enforcing following rules: - Block must have the proper
* last_hash reference - Block must meet the proof of work requirements -
* difficulty must only adjust by one - block hash must be a valid combination
* of block fields
*
* #param last_block
* #param block
* #return
* #throws NoSuchAlgorithmException
*/
public static boolean is_valid_block(Block last_block, Block block) throws NoSuchAlgorithmException {
String binary_hash = CryptoHash.hex_to_binary(block.getHash());
char[] pow_array = CryptoHash.n_len_array('0', block.getDifficulty());
char[] binary_char_array = CryptoHash.string_to_charray(binary_hash);
if (!block.getLastHash().equalsIgnoreCase(last_block.getHash())) {
System.out.println("The last hash must be correct");
return false;
// Throw exception the last hash must be correct
}
if (!Arrays.equals(pow_array, Arrays.copyOfRange(binary_char_array, 0, block.getDifficulty()))) {
System.out.println("Proof of work requirement not met");
return false;
// throw exception - proof of work requirement not met
}
if (Math.abs(last_block.difficulty - block.difficulty) > 1) {
System.out.println("Block difficulty must adjust by one");
return false;
// throw exception: The block difficulty must only adjust by 1
}
String reconstructed_hash = CryptoHash.getSHA256(block.getTimestamp(), block.getLastHash(), block.getData(),
block.getDifficulty(), block.getNonce());
if (!block.getHash().equalsIgnoreCase(reconstructed_hash)) {
System.out.println("The block hash must be correct");
System.out.println(block.getHash());
System.out.println(reconstructed_hash);
return false;
// throw exception: the block hash must be correct
}
System.out.println("You have mined a valid block");
return true;
}
public int getDifficulty() {
return difficulty;
}
public long getTimestamp() {
return timestamp;
}
public String getHash() {
return hash;
}
public String getLastHash() {
return lastHash;
}
public String[] getData() {
return data;
}
public int getNonce() {
return nonce;
}
public static void main(String[] args) throws NoSuchAlgorithmException {
// String md = CryptoHash.getSHA256("foobar");
Block genesis = genesis_block();
System.out.println(genesis.toString());
// Block bad_block = Block.mine_block(genesis, new String[] { "watch", "AOT" });
// bad_block.lastHash = "evil data";
// System.out.println(bad_block.toString());
Block good_block = mine_block(genesis, new String[] { "foo", "bar" });
System.out.println(good_block.toString());
// System.out.println(mine_block(new_block, new String[] { "crypto", "is", "fun" }).toString());
// System.out.println(Block.is_valid_block(genesis, bad_block)); // returns false as expected
System.out.println(Block.is_valid_block(genesis, good_block));
System.out.println(CryptoHash.hex_to_binary(good_block.getHash()));
Block good_block2 = mine_block(good_block, new String[] { "bar", "foo" });
Block good_block3 = mine_block(good_block2, new String[] { "bar", "foo" });
Block good_block4 = mine_block(good_block3, new String[] { "bar", "foo" });
// Block good_block5 = mine_block(good_block4, new String[] {"bar", "foo"});
// Block good_block6 = mine_block(good_block5, new String[] {"bar", "foo"});
}
}
package privblock.gerald.ryan.util;
import java.math.BigInteger;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
public class CryptoHash {
static HashMap<Character, String> HEX_TO_BIN_TABLE;
static {
HEX_TO_BIN_TABLE = new HashMap<Character, String>();
HEX_TO_BIN_TABLE.put('0', "0000");
HEX_TO_BIN_TABLE.put('1', "0001");
HEX_TO_BIN_TABLE.put('2', "0010");
HEX_TO_BIN_TABLE.put('3', "0011");
HEX_TO_BIN_TABLE.put('4', "0100");
HEX_TO_BIN_TABLE.put('5', "0101");
HEX_TO_BIN_TABLE.put('6', "0110");
HEX_TO_BIN_TABLE.put('7', "0111");
HEX_TO_BIN_TABLE.put('8', "1000");
HEX_TO_BIN_TABLE.put('9', "1001");
HEX_TO_BIN_TABLE.put('a', "1010");
HEX_TO_BIN_TABLE.put('b', "1011");
HEX_TO_BIN_TABLE.put('c', "1100");
HEX_TO_BIN_TABLE.put('d', "1101");
HEX_TO_BIN_TABLE.put('e', "1110");
HEX_TO_BIN_TABLE.put('f', "1111");
}
public static String getSHA256(String... sarray) throws NoSuchAlgorithmException {
String s = concat(sarray);
// System.out.printf("Hashing \"%s\"\n", s);
MessageDigest md;
md = MessageDigest.getInstance("SHA-256");
byte[] b = md.digest(s.getBytes(StandardCharsets.UTF_8));
BigInteger number = new BigInteger(1, b);
StringBuilder hexString = new StringBuilder(number.toString(16));
while (hexString.length() < 32) {
hexString.insert(0, '0');
}
String mds = hexString.toString();
// System.out.printf("hash is:\n%s\n", mds);
return hexString.toString();
}
public static String getSHA256(long timestamp, String last_hash, String[] data, int difficulty, int nonce)
throws NoSuchAlgorithmException {
String s = "";
s += Long.toString(timestamp);
s += last_hash;
s += concat(data);
s += Integer.toString(difficulty);
s += Integer.toString(nonce);
// System.out.printf("Hashing \"%s\"\n", s);
MessageDigest md;
md = MessageDigest.getInstance("SHA-256");
byte[] b = md.digest(s.getBytes(StandardCharsets.UTF_8));
BigInteger number = new BigInteger(1, b);
StringBuilder hexString = new StringBuilder(number.toString(16));
// System.out.println(hexString);
while (hexString.length() < 32) {
hexString.insert(0, '0');
}
String messageDigestString = hexString.toString();
// System.out.printf("hash is:\n%s\n", messageDigestString);
return hexString.toString();
}
public static char[] n_len_array(char c, int n) {
char[] ch = new char[n];
for (int i = 0; i<n; i++) {
ch[i] = c;
}
return ch;
}
public static String n_len_string(char c, int n) {
String s = "";
for (int i = 0; i<n; i++) {
s += c;
}
return s;
}
public static String concat(String... args) {
String s = "";
for (String $ : args) {
s += $;
}
// System.out.println(s);
return s;
}
public static char[] string_to_charray(String str) {
char[] ch = new char[str.length()];
for (int i = 0; i < str.length(); i++) {
ch[i] = str.charAt(i);
}
return ch;
}
public static String string_to_hex(String arg) {
return String.format("%064x", new BigInteger(1, arg.getBytes(StandardCharsets.UTF_8)));
}
public static String hex_to_binary(String hex_string) {
String binary_string = "";
for (int i = 0; i < hex_string.length(); i++) {
binary_string += HEX_TO_BIN_TABLE.get(hex_string.charAt(i));
}
return binary_string;
}
public static String string_to_binary(String raw_string) {
String hex_string = string_to_hex(raw_string);
String bin_string = hex_to_binary(hex_string);
return bin_string;
}
}
ps here's an example of a log I created. I created other cleaner logs too but this shows what we're working with. The first item represents time in milliseconds. The second represents the first four digits of the hash, which is directly below it, followed by the level of difficulty requirement string (what the second item needs to be, length n = difficulty level). The hash just never leads with four zeros, ever, so my hash function or call to the function must be broken in some way.
6479
1000
1000001010111011100110111010100100111010101001111110010101011101101101110000110100110110110000001010001000000010110001100111100111010100110001001001110111011010011100110000011111110100000100000100000010100001000110000111000101100010001111011000110011111101
0000
6479
0101
0101110111010100101010100000001011100011000001110001011011001101001111101011010011000111101101111111001001001010100110101101100111111011001011100101111000011100010001000000000011000111010000101101001000001010101010111001010000101001110011111101011011011000
0000
6479
1000
1000000001000101001110001110110000110111001101100001011000111010111110001011011010011111111101011001110011001001111011011110110010101010101100011011001001110001100010010101001011100001101011011101010000000100111100011011110100000101100111010100100110011101
0000
6479

I figured out the problem. It is indeed often returning 4 leading zeroes but the code as structured is clipping them off (because it doesn't think they have meaning). I noticed by logging that the length is not always a fixed 64byte/256 bit string. Here's the output:
256
1101111000010000100001110001010001010000001010111001100011010011110010001001010001010010100110111000110010000010001110110100100101000000001111111110011100000001010100000111001000111101010001010100110100000000111000100001000000010010010111011110110011110111
256
011001111101001000011111011001111110010110000011001011111010001011010110010100001011010011010010111101100010010111000010110010110111110001010101100000000101001000111110100111011100001110010010101011011000000101100001101110101101010001110000111111110000
252
0001100101110011101000000011000101011100111101110100111110100101110110011100010110001011000110010011110110011001100111010001100100011001011000001011100011011011011011101000111000011100100011011011011000101010011101000110101011000110011100111010000011000011
256
1100110001001001110001100111100010101100100010110111100111001010011011111111100010100110110000010000101000010111111010010101110001100010101010111111111111001011010111010100001010000010111100100100111000010101011000110000100000100111010001000011000000010000
256
So that's solved, or at least I understand the problem. It's amazing what sleep will do.

Changes required for using non-quantized tflite files in MainActivity.java

This MainActivity.java was written for quantised models and I'm trying to use unquantised model.
After making the changes as mentioned here, here to MainActivity.java, my code is
public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {
private static final String TAG = "MainActivity";
private Button mRun;
private ImageView mImageView;
private Bitmap mSelectedImage;
private GraphicOverlay mGraphicOverlay;
// Max width (portrait mode)
private Integer mImageMaxWidth;
// Max height (portrait mode)
private Integer mImageMaxHeight;
private final String[] mFilePaths =
new String[]{"mountain.jpg", "tennis.jpg","96580.jpg"};
/**
* Name of the model file hosted with Firebase.
*/
private static final String HOSTED_MODEL_NAME = "mobilenet_v1_224_quant";
private static final String LOCAL_MODEL_ASSET = "retrained_graph_mobilenet_1_224.tflite";
/**
* Name of the label file stored in Assets.
*/
private static final String LABEL_PATH = "labels.txt";
/**
* Number of results to show in the UI.
*/
private static final int RESULTS_TO_SHOW = 3;
/**
* Dimensions of inputs.
*/
private static final int DIM_BATCH_SIZE = 1;
private static final int DIM_PIXEL_SIZE = 3;
private static final int DIM_IMG_SIZE_X = 224;
private static final int DIM_IMG_SIZE_Y = 224;
private static final int IMAGE_MEAN = 128;
private static final float IMAGE_STD = 128.0f;
/**
* Labels corresponding to the output of the vision model.
*/
private List<String> mLabelList;
private final PriorityQueue<Map.Entry<String, Float>> sortedLabels =
new PriorityQueue<>(
RESULTS_TO_SHOW,
new Comparator<Map.Entry<String, Float>>() {
#Override
public int compare(Map.Entry<String, Float> o1, Map.Entry<String, Float>
o2) {
return (o1.getValue()).compareTo(o2.getValue());
}
});
/* Preallocated buffers for storing image data. */
private final int[] intValues = new int[DIM_IMG_SIZE_X * DIM_IMG_SIZE_Y];
/**
* An instance of the driver class to run model inference with Firebase.
*/
private FirebaseModelInterpreter mInterpreter;
/**
* Data configuration of input & output data of model.
*/
private FirebaseModelInputOutputOptions mDataOptions;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mGraphicOverlay = findViewById(R.id.graphic_overlay);
mImageView = findViewById(R.id.image_view);
Spinner dropdown = findViewById(R.id.spinner);
List<String> items = new ArrayList<>();
for (int i = 0; i < mFilePaths.length; i++) {
items.add("Image " + (i + 1));
}
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout
.simple_spinner_dropdown_item, items);
dropdown.setAdapter(adapter);
dropdown.setOnItemSelectedListener(this);
mLabelList = loadLabelList(this);
mRun = findViewById(R.id.button_run);
mRun.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
runModelInference();
}
});
int[] inputDims = {DIM_BATCH_SIZE, DIM_IMG_SIZE_X, DIM_IMG_SIZE_Y, DIM_PIXEL_SIZE};
int[] outputDims = {DIM_BATCH_SIZE, mLabelList.size()};
try {
mDataOptions =
new FirebaseModelInputOutputOptions.Builder()
.setInputFormat(0, FirebaseModelDataType.FLOAT32, inputDims)
.setOutputFormat(0, FirebaseModelDataType.FLOAT32, outputDims)
.build();
FirebaseModelDownloadConditions conditions = new FirebaseModelDownloadConditions
.Builder()
.requireWifi()
.build();
FirebaseLocalModelSource localModelSource =
new FirebaseLocalModelSource.Builder("asset")
.setAssetFilePath(LOCAL_MODEL_ASSET).build();
FirebaseCloudModelSource cloudSource = new FirebaseCloudModelSource.Builder
(HOSTED_MODEL_NAME)
.enableModelUpdates(true)
.setInitialDownloadConditions(conditions)
.setUpdatesDownloadConditions(conditions) // You could also specify
// different conditions
// for updates
.build();
FirebaseModelManager manager = FirebaseModelManager.getInstance();
manager.registerLocalModelSource(localModelSource);
manager.registerCloudModelSource(cloudSource);
FirebaseModelOptions modelOptions =
new FirebaseModelOptions.Builder()
.setCloudModelName(HOSTED_MODEL_NAME)
.setLocalModelName("asset")
.build();
mInterpreter = FirebaseModelInterpreter.getInstance(modelOptions);
} catch (FirebaseMLException e) {
showToast("Error while setting up the model");
e.printStackTrace();
}
}
private void runModelInference() {
if (mInterpreter == null) {
Log.e(TAG, "Image classifier has not been initialized; Skipped.");
return;
}
// Create input data.
ByteBuffer imgData = convertBitmapToByteBuffer(mSelectedImage, mSelectedImage.getWidth(),
mSelectedImage.getHeight());
try {
FirebaseModelInputs inputs = new FirebaseModelInputs.Builder().add(imgData).build();
// Here's where the magic happens!!
mInterpreter
.run(inputs, mDataOptions)
.addOnFailureListener(new OnFailureListener() {
#Override
public void onFailure(#NonNull Exception e) {
e.printStackTrace();
showToast("Error running model inference");
}
})
.continueWith(
new Continuation<FirebaseModelOutputs, List<String>>() {
#Override
public List<String> then(Task<FirebaseModelOutputs> task) {
float[][] labelProbArray = task.getResult()
.<float[][]>getOutput(0);
List<String> topLabels = getTopLabels(labelProbArray);
mGraphicOverlay.clear();
GraphicOverlay.Graphic labelGraphic = new LabelGraphic
(mGraphicOverlay, topLabels);
mGraphicOverlay.add(labelGraphic);
return topLabels;
}
});
} catch (FirebaseMLException e) {
e.printStackTrace();
showToast("Error running model inference");
}
}
/**
* Gets the top labels in the results.
*/
private synchronized List<String> getTopLabels(float[][] labelProbArray) {
for (int i = 0; i < mLabelList.size(); ++i) {
sortedLabels.add(
new AbstractMap.SimpleEntry<>(mLabelList.get(i), (labelProbArray[0][i] )));
if (sortedLabels.size() > RESULTS_TO_SHOW) {
sortedLabels.poll();
}
}
List<String> result = new ArrayList<>();
final int size = sortedLabels.size();
for (int i = 0; i < size; ++i) {
Map.Entry<String, Float> label = sortedLabels.poll();
result.add(label.getKey() + ":" + label.getValue());
}
Log.d(TAG, "labels: " + result.toString());
return result;
}
/**
* Reads label list from Assets.
*/
private List<String> loadLabelList(Activity activity) {
List<String> labelList = new ArrayList<>();
try (BufferedReader reader =
new BufferedReader(new InputStreamReader(activity.getAssets().open
(LABEL_PATH)))) {
String line;
while ((line = reader.readLine()) != null) {
labelList.add(line);
}
} catch (IOException e) {
Log.e(TAG, "Failed to read label list.", e);
}
return labelList;
}
/**
* Writes Image data into a {#code ByteBuffer}.
*/
private synchronized ByteBuffer convertBitmapToByteBuffer(
Bitmap bitmap, int width, int height) {
ByteBuffer imgData =
ByteBuffer.allocateDirect(
4*DIM_BATCH_SIZE * DIM_IMG_SIZE_X * DIM_IMG_SIZE_Y * DIM_PIXEL_SIZE);
imgData.order(ByteOrder.nativeOrder());
Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, DIM_IMG_SIZE_X, DIM_IMG_SIZE_Y,
true);
imgData.rewind();
scaledBitmap.getPixels(intValues, 0, scaledBitmap.getWidth(), 0, 0,
scaledBitmap.getWidth(), scaledBitmap.getHeight());
// Convert the image to int points.
int pixel = 0;
for (int i = 0; i < DIM_IMG_SIZE_X; ++i) {
for (int j = 0; j < DIM_IMG_SIZE_Y; ++j) {
final int val = intValues[pixel++];
imgData.putFloat((((val >> 16) & 0xFF)-IMAGE_MEAN)/IMAGE_STD);
imgData.putFloat((((val >> 8) & 0xFF)-IMAGE_MEAN)/IMAGE_STD);
imgData.putFloat(((val & 0xFF)-IMAGE_MEAN)/IMAGE_STD);
}
}
return imgData;
}
private void showToast(String message) {
Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();
}
public void onItemSelected(AdapterView<?> parent, View v, int position, long id) {
mGraphicOverlay.clear();
mSelectedImage = getBitmapFromAsset(this, mFilePaths[position]);
if (mSelectedImage != null) {
// Get the dimensions of the View
Pair<Integer, Integer> targetedSize = getTargetedWidthHeight();
int targetWidth = targetedSize.first;
int maxHeight = targetedSize.second;
// Determine how much to scale down the image
float scaleFactor =
Math.max(
(float) mSelectedImage.getWidth() / (float) targetWidth,
(float) mSelectedImage.getHeight() / (float) maxHeight);
Bitmap resizedBitmap =
Bitmap.createScaledBitmap(
mSelectedImage,
(int) (mSelectedImage.getWidth() / scaleFactor),
(int) (mSelectedImage.getHeight() / scaleFactor),
true);
mImageView.setImageBitmap(resizedBitmap);
mSelectedImage = resizedBitmap;
}
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
// Do nothing
}
// Utility functions for loading and resizing images from app asset folder.
public static Bitmap getBitmapFromAsset(Context context, String filePath) {
AssetManager assetManager = context.getAssets();
InputStream is;
Bitmap bitmap = null;
try {
is = assetManager.open(filePath);
bitmap = BitmapFactory.decodeStream(is);
} catch (IOException e) {
e.printStackTrace();
}
return bitmap;
}
// Returns max image width, always for portrait mode. Caller needs to swap width / height for
// landscape mode.
private Integer getImageMaxWidth() {
if (mImageMaxWidth == null) {
// Calculate the max width in portrait mode. This is done lazily since we need to
// wait for a UI layout pass to get the right values. So delay it to first time image
// rendering time.
mImageMaxWidth = mImageView.getWidth();
}
return mImageMaxWidth;
}
// Returns max image height, always for portrait mode. Caller needs to swap width / height for
// landscape mode.
private Integer getImageMaxHeight() {
if (mImageMaxHeight == null) {
// Calculate the max width in portrait mode. This is done lazily since we need to
// wait for a UI layout pass to get the right values. So delay it to first time image
// rendering time.
mImageMaxHeight =
mImageView.getHeight();
}
return mImageMaxHeight;
}
// Gets the targeted width / height.
private Pair<Integer, Integer> getTargetedWidthHeight() {
int targetWidth;
int targetHeight;
int maxWidthForPortraitMode = getImageMaxWidth();
int maxHeightForPortraitMode = getImageMaxHeight();
targetWidth = maxWidthForPortraitMode;
targetHeight = maxHeightForPortraitMode;
return new Pair<>(targetWidth, targetHeight);
}
}
But I'm still getting Failed to get input dimensions. 0-th input should have 268203 bytes, but found 1072812 bytes for inception and 0-th input should have 150528 bytes, but found 602112 bytes for mobilenet. So, a factor is 4 there always.
To see what I've changed, the output of diff original.java changed.java is: (Ignore the line numbers)
32a33,34
> private static final int IMAGE_MEAN = 128;
> private static final float IMAGE_STD = 128.0f;
150,151c152,153
< byte[][] labelProbArray = task.getResult()
< .<byte[][]>getOutput(0);
---
> float[][] labelProbArray = task.getResult()
> .<float[][]>getOutput(0);
170c172
< private synchronized List<String> getTopLabels(byte[][] labelProbArray) {
---
> private synchronized List<String> getTopLabels(float[][] labelProbArray) {
173,174c175
< new AbstractMap.SimpleEntry<>(mLabelList.get(i), (labelProbArray[0][i] &
< 0xff) / 255.0f));
---
> new AbstractMap.SimpleEntry<>(mLabelList.get(i), (labelProbArray[0][i] )));
214c215,216
< DIM_BATCH_SIZE * DIM_IMG_SIZE_X * DIM_IMG_SIZE_Y * DIM_PIXEL_SIZE);
---
> 4*DIM_BATCH_SIZE * DIM_IMG_SIZE_X * DIM_IMG_SIZE_Y * DIM_PIXEL_SIZE);
>
226,228c228,232
< imgData.put((byte) ((val >> 16) & 0xFF));
< imgData.put((byte) ((val >> 8) & 0xFF));
< imgData.put((byte) (val & 0xFF));
---
> imgData.putFloat((((val >> 16) & 0xFF)-IMAGE_MEAN)/IMAGE_STD);
> imgData.putFloat((((val >> 8) & 0xFF)-IMAGE_MEAN)/IMAGE_STD);
> imgData.putFloat(((val & 0xFF)-IMAGE_MEAN)/IMAGE_STD);

This is how the buffer is allocated in the code lab:
ByteBuffer imgData = ByteBuffer.allocateDirect(
DIM_BATCH_SIZE * DIM_IMG_SIZE_X * DIM_IMG_SIZE_Y * DIM_PIXEL_SIZE);
DIM_BATCH_SIZE - A typical usage is for supporting batch processing (if the model supports it). In our sample and probably your test, you feed 1 image at a time and just keep it as 1.
DIM_PIXEL_SIZE - We set 3 in the code lab, which corresponds to r/g/b 1 byte each.
However, looks like you are using a float model. Then instead of one byte each for r/g/b, you use a float (4 bytes) to represent r/g/b each (you figured out this part already yourself). Then the buffer you allocated using above code is no longer sufficient.
You can follow example here for float models:
https://github.com/tensorflow/tensorflow/blob/25b4086bb5ba1788ceb6032eda58348f6e20a71d/tensorflow/contrib/lite/java/demo/app/src/main/java/com/example/android/tflitecamerademo/ImageClassifierFloatInception.java
To be exact on imgData population, below should be the formula for allocation:
ByteBuffer imgData = ByteBuffer.allocateDirect(
DIM_BATCH_SIZE * getImageSizeX() * getImageSizeY() * DIM_PIXEL_SIZE
* getNumBytesPerChannel());
getNumBytesPerChannel() should be 4 in your case.
[Update for the new question, in regards of below error]:
Failed to get input dimensions. 0-th input should have 268203 bytes, but found 1072812 bytes
This is the check that number of bytes expected by the model == number of bytes passed in. 268203 = 299 * 299 * 3 & 1072812 = 4 * 299 * 299 * 3. Looks like you are using a quantized model but fed it with data for float model. Could you double check the model you used? To make things simple, don't specify cloud model source and use local model from assets only.
[Update 0628, developer said they trained a float model]:
It could be your model is wrong; it could also be you have a Cloud model downloaded which overrides your local model. But the error message tells us that the model being loaded is NOT a float model.
To isolate the issue, I'd recommend below few testings:
1) Remove setCloudModelName / registerCloudModelSource from quick start app
2) Play with official TFLite float model You will have to download the model mentioned in comment and change Camera2BasicFragment to use that ImageClassifierFloatInception (instead of ImageClassifierQuantizedMobileNet)
3) Still use the same TFLite sample app, switch to your own trained model. Make sure to tune the image size to your values.

Decompress a string with more nested strings

The assignment consists in decompress a string. In particular, the code has to work for 3 samples as illustrated in the picture.
My code here works in the first 2 of the samples. However, I am not able to come up with the 3rd sample. Probably I did not understand probably the concept of recursion. Can you help me?
import java.util.Scanner;
public class Compression4 {
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
String input=in.next();
System.out.println(uncompress(input));
}
public static boolean flag = true;
public static String uncompress(String compressedText)
{
return uncompress(compressedText, "", "");
}
public static String getMultiple(String x, int N) {
if (N == 0) return "";
return ""+x+getMultiple(x,N-1);
}
public static String uncompress(String text, String count, String output)
{
if (text.equals(""))
{
return output;
}
if(text.charAt(0) == '(')
{
int FirstIndex = text.indexOf("(")+1;
String inner = text.substring(FirstIndex, text.lastIndexOf(")"));
//System.out.println(inner);
flag = false;
return uncompress (inner, count, output);
}
else if (Character.isLetter(text.charAt(0)))
{
//letter case - need to take the count we have accrued, parse it into an integer and add to output
if (flag==true)
{
//System.out.println(count);// * text.charAt(0);
String s = String.valueOf(text.charAt(0));
output += getMultiple(s,Integer.parseInt(count));
count ="1";
}
else
{
//System.out.println(count);// * text.charAt(0);
output += getMultiple(text,Integer.parseInt(count));
//System.out.println("output: "+output);
count="0";
}
}
else if(Character.isDigit(text.charAt(0)))
{
//digit case - need to add to the count but keep as a string because must be parsed later
if(flag)
count += (""+text.charAt(0));
else
{
count = "0";
count += (""+text.charAt(0));
}
}
//parse the *remainder* of the string, one character at a time, so pass in the substring(1)
return uncompress(text.substring(1), count, output);
}
}

Sorry for the long code but it's more easy to explain with code than with words.
Premise:
I think to the problem as an interpreter of a language to render a string
the language is simple and functional so recursive interpretation is possible
Algorithm phases:
First: tokenize the expression (to work at an higher level of abstraction)
Second: parse the expression just tokenized
Recursion: the logic is based on the syntax of the language. Key concepts of a recursion:
the base cases and the recursive cases
the state necessary to a single recursion (local variables of recursion, those passed as parameters to the recursive method)
the state for the all recursion (global variables of recursion, those read/write in some specific recursion)
I've made many comments to explain what the algorithm is doing. If it's not clear I can explain it better.
import java.util.ArrayList;
import java.util.List;
public class TestStringDecompression {
// simpleExpr examples: a | b | 123a | 123b | 123(a) | 123(ab) | 123(ba) | (ab) | (ba)
// 11ab = aaaaaaaaaaab = = expression = simpleExpr simpleExpr = 11a b
// 4(ab) = abababab = expression = simpleExpr = 4(ab)
// 2(3b3(ab)) = bbbabababbbbababab = expression = compositeExpr = 2 ( simpleExpr simpleExpr ) = 2 ( 3b 3(ab) )
public static void main(String[] args) {
System.out.println(new StringInflater().inflate("11ab"));
System.out.println(new StringInflater().inflate("4(ab)"));
System.out.println(new StringInflater().inflate("2(3b3(ab))"));
}
public static class StringInflater {
// This store the position of the last parsed token
private int posLastParsedToken = 0;
public String inflate(String expression) {
return parse(tokenize(expression), 0, false);
}
/**
* Language tokens:
* <ul>
* <li>literals:
* <ul>
* <li>intLiteral = [0-9]*</li>
* <li>charLiteral = [ab]</li>
* </ul>
* </li>
* <li>separators:
* <ul>
* <li>leftParen = '('</li>
* <li>rightParen = ')'</li>
* </ul>
* </li>
* </ul>
*/
private Object[] tokenize(String expression) {
List<Object> tokens = new ArrayList<Object>();
int i = 0;
while (i < expression.length()) {
if ('0' <= expression.charAt(i) && expression.charAt(i) <= '9') {
String number = "";
while ('0' <= expression.charAt(i) && expression.charAt(i) <= '9' && i < expression.length()) {
number += expression.charAt(i++);
}
tokens.add(Integer.valueOf(number));
} else {
tokens.add(expression.charAt(i++));
}
}
return tokens.toArray(new Object[tokens.size()]);
}
/**
* Language syntax:
* <ul>
* <li>simpleExpr = [intLiteral] charLiteral | [intLiteral] leftParen charLiteral+ rightParen</li>
* <li>compositeExpr = [intLiteral] leftParen (simpleExpr | compositeExpr)+ rightParen</li>
* <li>expression = (simpleExpr | compositeExpr)+</li>
* </ul>
*/
private String parse(Object[] tokens, int pos, boolean nested) {
posLastParsedToken = pos;
String result = "";
if (tokens[pos] instanceof Integer) {
/** it's a intLiteral */
// get quantifier value
int repetition = (int) tokens[pos];
// lookahead for (
if (tokens[pos + 1].equals("(")) {
// composite repetition, it could be:
// simpleExpr: "[intLiteral] leftParen charLiteral+ rightParen"
// compositeExpr: "[intLiteral] leftParen (simpleExpr | compositeExpr)+ rightParen"
result = parse(tokens, pos + 1, true);
} else {
// simple repetition, it could be:
// simpleExpr: [intLiteral] charLiteral
result = parse(tokens, pos + 1, false);
}
result = repeat(result, repetition);
// evaluate the rest of the expression because syntax allows it
if (posLastParsedToken + 1 == tokens.length) {
// end of the expression
return result;
} else {
// there are other simpleExpr or compositeExpr to parse
return result + parse(tokens, posLastParsedToken + 1, false);
}
} else if (tokens[pos].equals('(')) {
/** it's a leftParen */
// an open paren means what follow this token is considered nested (useful for string to treat as char sequence)
return parse(tokens, pos + 1, true);
} else if (tokens[pos].equals(')')) {
/** it's a rightParen */
// a closed paren, nothing to render
return "";
} else {
/** it's a charLiteral */
if (nested) {
// it's nested between paren, so more parsing is requested to consume next charLiteral or next simpleExpr or compositeExpr
return tokens[pos] + parse(tokens, pos + 1, nested);
} else {
// it's not nested between paren, return charLiteral as is
return "" + tokens[pos];
}
}
}
private String repeat(String s, int repetition) {
StringBuilder result = new StringBuilder();
for (int i = 0; i < repetition; i++) {
result.append(s);
}
return result.toString();
}
}
}

Search for a String (as an byte[]) in a binary stream

Hi Team, I am trying to find a String "Henry" in a binary file and change the String to a different string. FYI the file is the output of serialisation of an object. Original Question here
I am new to searching bytes and imagined this code would search for my byte[] and exchange it. But it doesn't come close to working it doesn't even find a match.
{
byte[] bytesHenry = new String("Henry").getBytes();
byte[] bytesSwap = new String("Zsswd").getBytes();
byte[] seekHenry = new byte[bytesHenry.length];
RandomAccessFile file = new RandomAccessFile(fileString,"rw");
long filePointer;
while (seekHenry != null) {
filePointer = file.getFilePointer();
file.readFully(seekHenry);
if (bytesHenry == seekHenry) {
file.seek(filePointer);
file.write(bytesSwap);
break;
}
}
}
Okay I see the bytesHenry==seekHenry problem and will swap to Arrays.equals( bytesHenry , seekHenry )
I think I need to move along by -4 byte positions each time i read 5 bytes.
Bingo it finds it now
while (seekHenry != null) {
filePointer = file.getFilePointer();
file.readFully(seekHenry);;
if (Arrays.equals(bytesHenry,
seekHenry)) {
file.seek(filePointer);
file.write(bytesSwap);
break;
}
file.seek(filePointer);
file.read();
}

The following could work for you, see the method search(byte[] input, byte[] searchedFor) which returns the index where the first match matches, or -1.
public class SearchBuffer {
public static void main(String[] args) throws UnsupportedEncodingException {
String charset= "US-ASCII";
byte[] searchedFor = "ciao".getBytes(charset);
byte[] input = "aaaciaaaciaojjcia".getBytes(charset);
int idx = search(input, searchedFor);
System.out.println("index: "+idx); //should be 8
}
public static int search(byte[] input, byte[] searchedFor) {
//convert byte[] to Byte[]
Byte[] searchedForB = new Byte[searchedFor.length];
for(int x = 0; x<searchedFor.length; x++){
searchedForB[x] = searchedFor[x];
}
int idx = -1;
//search:
Deque<Byte> q = new ArrayDeque<Byte>(input.length);
for(int i=0; i<input.length; i++){
if(q.size() == searchedForB.length){
//here I can check
Byte[] cur = q.toArray(new Byte[]{});
if(Arrays.equals(cur, searchedForB)){
//found!
idx = i - searchedForB.length;
break;
} else {
//not found
q.pop();
q.addLast(input[i]);
}
} else {
q.addLast(input[i]);
}
}
return idx;
}
}

From Fastest way to find a string in a text file with java:
The best realization I've found in MIMEParser: https://github.com/samskivert/ikvm-openjdk/blob/master/build/linux-amd64/impsrc/com/sun/xml/internal/org/jvnet/mimepull/MIMEParser.java
/**
* Finds the boundary in the given buffer using Boyer-Moore algo.
* Copied from java.util.regex.Pattern.java
*
* #param mybuf boundary to be searched in this mybuf
* #param off start index in mybuf
* #param len number of bytes in mybuf
*
* #return -1 if there is no match or index where the match starts
*/
private int match(byte[] mybuf, int off, int len) {
Needed also:
private void compileBoundaryPattern();