What I need to do is take a String array with each element having an exact length of 2, and find all possible combinations of the the elements, using each character within each String. By that I mean the String array {"Ss", "Ff"} returns "SF", "Sf", "sF", "sf". I have already tried a loop method that counts the iteration and then chooses a letter based on that, but it only works for arrays with a single element:
public String [] generatePossibilities(String [] s)
{
if(s[0].length() != 2)
throw new IllegalArgumentException();
String [] r = new String [s.length * 2];
for(int i = 0; i < r.length; i++)
{
r[i] = getPossibility(i, s);
}
return r;
}
private String getPossibility(int iteration, String [] source)
{
int [] choose = new int [source.length];
for(int i = 0; i < choose.length; i++)
{
choose[i] = 0;
}
for(int i = choose.length - 1; i >= 0; i--)
{
if(iteration < 1)
break;
choose[i] = 1;
iteration--;
}
String result = "";
for(int i = 0; i < source.length; i++)
result += source[i].substring(choose[i], choose[i] + 1);
return result;
}
Solved Thanks Sven!
public String [] generatePossibilities(String [] s)
{
if(s[0].length() != 2)
throw new IllegalArgumentException();
ArrayList<String> ra = new ArrayList<String>();
for(int i = s.length - 1; i >= 0; i--)
{
for(int j = 0; j < s[i].length(); j++)
{
String c = s[i].substring(j, j + 1);
if(ra.size() < 2)
{
ra.add(c);
}
else
{
for(int k = 0; k < ra.size(); k++)
{
String s1 = ra.get(k);
if(s1.substring(0, 1).equalsIgnoreCase(c))
continue;
else
{
s1 = c + s1;
ra.add(s1);
}
}
}
}
for(int j = 0; j < ra.size(); j++)
{
if(ra.get(j).length() != s.length - i)
{
ra.remove(j);
j--;
}
}
}
String [] r = new String [ra.size()];
for(int i = 0; i < r.length; i++)
{
r[i] = ra.get(i);
}
return r;
}
I would iterate the array of character tuples from last element to first. In each step you append to each current character the possibilities of the last iteration. You therefore double the elements in each step.
So for your example in the first iteration you have {Ff} and this would result to the two strings "F" and "f". In the next step you take each character of {Ss} and append each string of the last step to it getting "SF", "Sf", "sF" and "sf". You could then continue with further character tuples.
Related
Hi I am trying to mark a position that already been visited
This string
String s = "123+4+3233"
and multiple index.
So I will loop it gotta be inner loop
public static void main(String[] args) {
String s = "123+4+3233";
String n = "";
int count = 0;
List<String> lists = new ArrayList<>();
for(int i=0; i < s.length(); i++){
if(s.charAt(i) > 0){
for(int k = i; k < s.length(); k++){
if(s.charAt(k) == '+'){
break;
}
if(s.charAt(k) != '+'){
n += s.charAt(k);
}
}
if(!(n.isEmpty())){
lists.add(n);
n = "";
}
if(s.charAt(i) == '+'){count++; }
}
}
System.out.println(lists);
}
and this result would come out Since I don't know how to mark the place that already visited.
CANNOT USE SPLIT
[123, 23, 3, 4, 3233, 233, 33, 3]
I just want
EXPECTED RESULT
[123, 4, 3233]
you don't have to mark the place that visited, simply advance the i index:
public static void main(String[] args) {
String s = "123+4+3233";
String n = "";
int count = 0;
List<String> lists = new ArrayList<>();
for(int i=0; i < s.length(); i++){
if(s.charAt(i) > 0){
int k = i;
for(; k < s.length(); k++){
if(s.charAt(k) == '+'){
break;
}
if(s.charAt(k) != '+'){
n += s.charAt(k);
}
}
if(!(n.isEmpty())){
lists.add(n);
n = "";
}
if(s.charAt(i) == '+'){count++; }
if(k > i)i = k - 1; //advance i to the right position
}
}
System.out.println(lists);
}
output:
[123, 4, 3233]
I think you are complicating this one a bit. Here's how I would solve it:
String s = 123+4+3233;
ArrayList<String> nums = new ArrayList<>();
int lastPlus = 0; // Keeping track of the last index at which there was a "+"
for (int j = 0 j < s.length(); j++) {
if (s.charAt(j).equals("+")) {
nums.add(s.substring(lastPlus, j));
lastPlus = j + 1; //The "+1" skips over the plus for the next substring()
}
// This last 'if' statement is for adding that last bit of numbers
if (j == s.length() - 1 && !(s.charAt(j).equals("+"))) {
nums.add(lastPlus);
}
}
This should work.
I think it can be done in a shorter way:
public static void main(String... args){
String s = "123+4+3233";
List<String> lists = new ArrayList<>();
for(int i = 0; i<s.length();i++){
String temp = "";
while(i<s.length() && s.charAt(i) != '+'){
temp+= s.charAt(i);
i++;
}
lists.add(temp);
}
System.out.println(lists);
}
I have seen many resources from the internet but couldn't found the exact help. i am trying to figure out the edit distance between the two strings example:
String a = "put return between paragraph gioo";
String b = "put hello between line phone gio";
here I am always comparing with String a with the other string so here the edit distance should be 4.
I have done some code execution its comparing me with the each character in the string.
int len1 = row10.length();
int len2 = row01.length();
int[][] dp = new int[len1 + 1][len2 + 1];
for (int i = 0; i <= len1; i++) {
dp[i][0] = i;
}
for (int j = 0; j <= len2; j++) {
dp[0][j] = j;
}
for (int i = 0; i < len1; i++) {
char c1 = row10.charAt(i);
for (int j = 0; j < len2; j++) {
char c2 = row01.charAt(j);
if (c1 == c2) {
dp[i + 1][j + 1] = dp[i][j];
} else {
int replace = dp[i][j] + 1;
int insert = dp[i][j + 1] + 1;
int delete = dp[i + 1][j] + 1;
int min = replace > insert ? insert : replace;
min = delete > min ? min : delete;
dp[i + 1][j + 1] = min;
}
}
}
System.out.println(dp[len1][len2]);
Made a sample function. It doesn't really take into the consideration of corner cases but it works. Also, do think about the case sensitivity of the words.
package test;
public class CalcWordDiff {
public static void main(String[] args) {
// TODO Auto-generated method stub
String a = "My name is ABC.";
String b = "My name xyz.";
System.out.println("Edit distance will be : "+calcDistanceBetweenWords(a,b));
}
public static int calcDistanceBetweenWords(String first, String second)
{
int res = 0;
String[] words_string_first = first.trim().split(" "); // By trim, I removed the Whitespaces if they exist
String[] words_string_second = second.trim().split(" ");
//Check the length of both the arrays
System.out.println("Size of arrays first is : "+words_string_first.length);
System.out.println("Size of arrays second is : "+words_string_second.length);
int lowerWordSentSize = 0;
if(words_string_first.length<=words_string_second.length)
{
lowerWordSentSize = words_string_first.length;
}
else
{
lowerWordSentSize = words_string_second.length;
}
//Now iterate through the array of lower size
for(int i = 0; i< lowerWordSentSize; i++)
{
if(words_string_first[i].equals(words_string_second[i]))
{
//Do nothing, it means both the words are same
}
else
{
System.out.println("Words mismatched at "+(i+1)+" th Position.");
res = i;
}
}
return res;
}
}
This question already has answers here:
Counting the number of a certain letter appears in series of strings in an ArrayList
(4 answers)
Closed 6 years ago.
I have an ArrayList that stores strings, or notes, in the form of "walk the dog". I have a notes class with a method that prints the number of times each letter appears in the entire ArrayList. I'm supposed to declare and use a primitive array of ints of size 26 and turn each letter in the notebook into a char using the charAt method in the String class. Then I have to use that char to index into the appropriate location in the low-level array. This is my method so far but it's not finished:
public void printLetterDistribution() {
ArrayList<Integer> aList = new ArrayList<Integer>();
for (int i = 0; i < notes.size(); i++) {
String note = notes.get(i);
for (int j = 0; j < note.length(); j++) {
char letter = note.charAt(j);
int code = (int)letter;
aList.add(code);
}
}
Collections.sort(aList);
}
I've hit a wall and I don't know how to continue. As you can see, I've tried to convert the letters to their character code but it's probably not the best way to do it and I'm still getting stuck. Can anybody help?
EDIT - Here is the entire notes class:
public class Notebook {
private ArrayList<String> notes;
public Notebook() { notes = new ArrayList<String>(); }
public void addNoteToEnd(String inputnote) {
notes.add(inputnote);
}
public void addNoteToFront(String inputnote) {
notes.add(0, inputnote);
}
public void printAllNotes() {
for (int i = 0; i < notes.size(); i++) {
System.out.print("#" + (i + 1) + " ");
System.out.println(notes.get(i));
}
System.out.println();
}
public void replaceNote(int inputindex, String inputstring) {
int index = inputindex - 1;
if (index > notes.size() || index < 0) {
System.out.println("ERROR: Note number not found!");
} else {
notes.set(index, inputstring);
}
}
public int countNotesLongerThan(int length) {
int count = 0;
for (int i = 0; i < notes.size(); i++) {
String temp = notes.get(i);
if (temp.length() > length) {
count++;
}
}
return count;
}
public double averageNoteLength() {
int sum = 0;
for (int i = 0; i < notes.size(); i++) {
String temp = notes.get(i);
int length = temp.length();
sum += length;
}
double average = (double)(sum / notes.size());
return average;
}
public String firstAlphabetically() {
String min = "";
for (int i = 0; i < notes.size(); i++) {
for (int j = i + 1; j < notes.size(); j++) {
if ((notes.get(i)).compareTo(notes.get(j)) < 0) {
min = notes.get(i);
} else {
min = notes.get(j);
}
}
}
return min;
}
public void removeNotesBetween(int startnote, int endnote) {
int start = startnote - 1;
int end = endnote - 1;
for (int i = end - 1; i > start; i--) {
notes.remove(i);
}
}
public void printNotesContaining(String findString) {
for (int i = 0; i < notes.size(); i++) {
if (notes.get(i).contains(findString)) {
System.out.println("#" + i + " " + notes.get(i));
}
}
}
public int countNumberOf(String letter) {
int count = 0;
for (int i = 0; i < notes.size(); i++) {
String note = (notes.get(i));
for (int j = 0; j < note.length(); j++) {
if (note.charAt(j) == letter.charAt(0)) {
count++;
}
}
}
return count;
}
public void findAndReplaceFirst(String old, String newWord) {
for (int i = 0; i < notes.size(); i++) {
String note = notes.get(i);
if (note.contains(old)) {
int loc = note.indexOf(old);
int len = old.length();
String temp = note.substring(0, loc ) + note.substring(loc + len, note.length());
String newString = temp.substring(0, loc) + newWord + temp.substring(loc, temp.length());
notes.set(i, newString);
} else {
String newString = note;
notes.set(i, newString);
}
}
}
public void printLetterDistribution() {
int[] p = new int[26];
for (int i = 0; i < 26; i++) {
p[i] = 0;
}
for (int i = 0; i < notes.size(); i++) {
String note = notes.get(i);
note = note.toLowerCase();
for (int j = 0; j < note.length(); j++) {
char letter = note.charAt(j);
p[letter - 'a']++;
}
}
System.out.println(p);
}
}
You can use an int array of 26 length and increment the count of the index letter-'a';
int[] p = new int[26];
for(int i = 0; i < 26; i++) p[i] = 0;
for (int i = 0; i < notes.size(); i++) {
String note = notes.get(i);
for (int j = 0; j < note.length(); j++) {
char letter = note.charAt(j);
if(letter>= 'a' && letter <= 'z')
p[letter-'a']++;
}
PS: I am assuming that the notes are in lowercase only. If it is not the case, use note.toLowerCase() to make them lower.
Since in your notes you can have spaces, I have updated the code.
I'm trying to sort the characters alphabetically in a String and when I run my code with the following example: hello, then I get: heeeeeeeeeheeeelheeellhee instead of ehllo. Could smb suggest me what I should fix in my code? Thanks in advance!
public static void main(String[] args)
{
String result = "";
Scanner kbd = new Scanner(System.in);
String input = kbd.nextLine();
char[] myArray = input.toCharArray();
for(int i = 0; i < myArray.length; i++)
for(int j = 0; j < myArray.length; j++)
{
if(myArray[i] > myArray[j])
{
char temp = myArray[j];
myArray[j] = myArray[i];
myArray[i] = temp;
result += myArray[i];
}
else
result += myArray[i];
}
System.out.println(result);
}
Why so complicated?
public String sortByChar(String s)
{
char[] cs = s.toCharArray();
Arrays.sort(cs);
return new String(cs);
}
On each iteration of your loop, you appending the character at i within the array to result, but the array is not sorted yet
The loop will perform n * (n - 1) loops, so, for a String of 5 characters, that's going to be 5 * (5 - 1) (or 20) iterations.
Instead, sort the array and then create a new String based on it's content...
String input = "hello";
char[] myArray = input.toCharArray();
for (int i = 0; i < myArray.length; i++) {
for (int j = 1; j < myArray.length; j++) {
if (myArray[i] > myArray[j]) {
char temp = myArray[j];
myArray[j] = myArray[i];
myArray[i] = temp;
}
}
}
System.out.println(new String(myArray));
Also note, for (int j = 0; j < myArray.length; j++) { is wrong and should be for (int j = 1; j < myArray.length; j++) {, otherwise you'll be comparing the same character at the same position, which isn't what you want to do...
A more "accurate" bubble sort might look something like...
for (int i = 0; i < (myArray.length - 1); i++) {
for (int j = 0; j < myArray.length - i - 1; j++) {
if (myArray[j] > myArray[j + 1]) {
char swap = myArray[j];
myArray[j] = myArray[j + 1];
myArray[j + 1] = swap;
}
}
}
You keep modifying result as you go. This is wrong: result collects a record of characters as you modify them, which is not what you want.
You should remove result += ... from your code, and use this after the loop:
String result = new String(myArray);
How do I make it so that when I output the grid when I run the code, no two numbers or letters will be the same? When I currently run this code I could get 3x "L" or 2x "6", how do I make it so that they only appear once?
package polycipher;
import java.util.ArrayList;
public class Matrix {
private char[][] matrix = new char[6][6];
private int[] usedNumbers = new int[50];
{for(int x = 0; x < usedNumbers.length; x++) usedNumbers[x] = -1;}
private final char[] CIPHER_KEY = {'A','D','F','G','V','X'};
private final String validChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
public Matrix() {
int random;
for(int i = 0; i < CIPHER_KEY.length; i++) {
for(int j = 0; j < CIPHER_KEY.length; j++) {
validation: while(true) {
random = (int)(Math.random()*validChars.length()-1);
for(int k = 0; k < usedNumbers.length; k++) {
if(random == usedNumbers[k]) continue validation;
else if(usedNumbers[k]==-1) usedNumbers[k] = random;
}
break;
}
matrix[i][j] = validChars.split("")[random].charAt(0);
}
}
}
public String toString() {
String output = " A D F G V X\n";
for(int i = 0; i < CIPHER_KEY.length; i++) {
output += CIPHER_KEY[i] + " ";
for(int j = 0; j < CIPHER_KEY.length; j++) {
output += matrix[i][j] + " ";
}
output += "\n";
}
return output;
}
}
This should be much faster than validating each random choice:
Store your valid chars into an array;
char[] valid = validChars.toCharArray();
Shuffle the array;
shuffle(valid)
Go through the positions in the matrix, storing the elements in the same order they appear in the shuffled array.
assert (CIPHER_KEY.length * CIPHER_KEY.length) <= valid.length;
int k = 0;
for (int i = 0; i < CIPHER_KEY.length; i++) {
for (int j = 0; j < CIPHER_KEY.length; j++) {
matrix[i][j] = valid[k++];
}
}
Use a set and generate a new random if the old random number is in the map:
Pseudocode:
Set<Integer> set = new HashSet<Integer>();
for () {
int random = (int)(Math.random()*validChars.length()-1);
//Your code for validation here (move it to a function)
while (!set.contains(random)){
int random = (int)(Math.random()*validChars.length()-1);
//Your code for validation here (move it to a function)
}
//If we exit this loop it means the set doesn't contain the number
set.add(random);
//Insert your code here
}