I'm currently writing a HugeInteger class that can take in 40 digits, and I have a few comparison tests that are already written. The thing I'm having most trouble with is adding and subtraction methods. I was able to get two values to add, but don't know how to implement a negate function if one of the values are negative. My subtraction method doesn't seem to work either.
public void add(HugeInteger hi) {
if (digits[NUM_DIGITS] < 0) {
negate();
this.subtract(hi);
}
int carry = 0;
for(int i = digits.length-1; i >=0 ;i--) {
int cur = this.digits[i] + hi.digits[i] + carry;
if (cur >= 10){
cur= cur-10;
resultAdd[i] = cur;
carry = 1;
} else{
resultAdd[i] = cur;
carry = 0;
}
}
StringBuilder builder = new StringBuilder();
int j=0;
for (int i : resultAdd) {
builder.append(i);
this.digits[j] = i;
j++;
}
this.hi = builder.toString().replace("0", "");
}
public void subtract(HugeInteger hi) {
for(int i = digits.length-1; i >=0 ;i--) {
if (this.digits[i] - hi.digits[i] < 0){
this.digits[i-1]--;
this.digits[i]+=10;
}
int cur = this.digits[i] - hi.digits[i];
this.digits[i] = cur;
}
StringBuilder builder = new StringBuilder();
int j=0;
for (int i : resultAdd) {
builder.append(i);
this.digits[j] = i;
j++;
}
this.hi = builder.toString().replace("0", "");
}
public void negate() {
if(this.positive){
this.positive = false;
} else{
this.positive = true;
this.hi = this.hi.replace("-", "");
}
}
I need help with this program because it is not compiling correctly.
The program is supposed to do this:
java PostfixToInfix
1 2 3 + *
1*(2+3)
I am getting these errors when compiling:
PostfixToInfix.java:64: error: bad operand types for binary operator '-'
s.push(o2 - o1);
^
first type: String
second type: String
PostfixToInfix.java:68: error: bad operand types for binary operator '*'
s.push(o1 * o2);
^
first type: String
second type: String
2 errors
How many I supposed to code this so that it works properly? I am unsure what is wrong with my code that it is not allowing it do the functions properly.
This is my code:
import java.util.Scanner;
import java.util.Stack;
public class PostfixToInfix
{
public static void main(String[] args)
{
String[] input = readExpr();
if(checkSyntax(input) == true)
{
int k = 0;
Stack<String> s = new Stack<>();
for(int i = 0; i < input.length; ++i)
{
if(isOperator(input[i]))
{
String o1;
String o2;
if(!(s.empty()))
{
o1 = s.pop();
}
else
{
for(int j = 0; j < i; ++j)
{
k += input[j].length() + 1;
}
System.out.println("Too few operands for " + input[i]);
writeExpr(input);
for(int l = 0; l < k; ++l)
{
System.out.print(" ");
}
System.out.println("^");
return;
}
if(!(s.empty()))
{
o2 = s.pop();
}
else
{
for(int j = 0; j < i; ++j)
{
k += input[j].length() + 1;
}
System.out.println("Too few operands for " + input[i]);
writeExpr(input);
for(int l = 0; l < k; ++l)
{
System.out.print(" ");
}
System.out.println("^");
return;
}
if(input[i].equals("+"))
{
s.push(o1 + o2);
}
else if(input[i].equals("-"))
{
s.push(o2 - o1);
}
else
{
s.push(o1 * o2);
}
}
else
{
s.push(input[i]);
}
}
String Result = s.pop();
if(!(s.empty()))
{
System.out.println("Too few operators to produce a single result");
}
else
{
System.out.println(Result);
}
}
} // end main
static String[] readExpr()
{
Scanner stdin = new Scanner(System.in);
String s = stdin.nextLine();
String[] sA = s.split(" ");
return sA;
}
static void writeExpr(String[] expr)
{
for(int i = 0; i < expr.length; ++i)
{
System.out.print(expr[i] + " ");
}
System.out.println();
}
static boolean isOperator(String s)
{
if(s.equals("+") || s.equals("-") || s.equals("*"))
{
return true;
}
return false;
}
static boolean checkSyntax(String[] expr)
{
int k = 0;
for(int i = 0; i < expr.length; ++i)
{
if(!(isOperator(expr[i])))
{
try
{
Double.parseDouble(expr[i]);
}
catch (Exception e)
{
for(int j = 0; j < i; ++j)
{
k += expr[j].length() + 1;
}
writeExpr(expr);
for(int l = 0; l < k; ++l)
{
System.out.print(" ");
}
System.out.println("^");
System.out.println("Not a number or valid operator");
return false;
}
}
}
return true;
}
} // end Postfix2
class StringStack
{
int top;
String[] pancake;
StringStack() //constructor for a new empty stack
{
top = 0;
pancake = new String[1000];
} // end DoubleStack
boolean empty() //whether the stack is empty
{
return top == 0;
} // end empty
String pop() //remove and return the top element; throw an error if empty
{
if(empty())
{
throw new Error("Error");
}
top -= 1;
return pancake[top];
} // end pop
void push(String x) //add x to the top of the stack
{
if(top < 1000)
{
pancake[top] = x;
top += 1;
}
else{
throw new Error("Error");
}
} // end push
} // end StringStack
Change you code like this.
if(input[i].equals("+"))
{
s.push(o1 + "+" + o2);
}
else if(input[i].equals("-"))
{
s.push(o2 + "-" + o1);
}
else
{
s.push(o1 + "*" + o2);
}
But the result for "1 2 3 + *" is "3+2*1".
It is another problem.
Im at a point in my program where I need to set marks in a string before I pass it through another method, I have it so that every 4th char will have a "|" inserted, this is to mark a row break. Not I want to take each char in between the outter marks "|" and put a ",". that two char array method wont work here otherwise I would have tryed to use that but I'm not looking for a char array.
public static String matrixFormatter(String x){
x = x.substring(0, 4) + "|" + x.substring(4, x.length());
return x;
}
this works so far, now I want to add a "," between each char, I thought the code below would work and this would be easy but I was wrong.
public static String matrixFormatter(String x){
for(int i = 0; i<=x.length(); i+=4){
for(int j = 0; j<=x.length(); i++){
x = x.substring(0, i) + "|" + x.substring(i, x.length());
x = x.substring(0, j) + "|" + x.substring(j, x.length());
}
}
return x;
}
The code below adds a "," between characters in the string.
public static String matrixFormatter(String x){
String result;
for(int i = 0; i<x.length()-1; i++){
result += x.substring(i, i+1) + ",";
}
return result+",";
}
try this regex
s = s.replaceAll("(?<=.)(?=.)", ",");
It can be done with StringBuffer and also with Joiner of Guava library:
public static void main(String[] args) {
String s = "example";
System.out.println(withBuilder(s));
System.out.println(withJoiner(s));
}
private static String withJoiner(String s) {
return Joiner.on(",").join(Chars.asList(s.toCharArray()));
}
private static String withBuilder(String s)
{
StringBuilder builder = new StringBuilder(s);
int index = 1;
for (int i = 0; i < s.length() ; i++)
{
builder.insert(index, ",");
index +=2;
}
return builder.toString();
}
Output is:
e,x,a,m,p,l,e,
e,x,a,m,p,l,e
It can be done in one method:
public static String matrixFormatter(String x) {
List<String> chars = Arrays.asList(x.split(""));
String result = chars.get(0);
for (int i = 1; i < chars.size(); i++) {
if (i % 4 == 0)
result += "|" + chars.get(i);
else
result += "," + chars.get(i);
}
return result;
}
calling with:
System.out.println(matrixFormatter("12345678"));
outputs:
1,2,3,4|5,6,7,8
public static String matrixFormatter(String x) {
resultstr = "";
int i = 0;
while(i < x.length()) {
// If end of string: only add character.
if (i == x.length() - 1) {
resultstr += x.substring(i, i + 1);
} else {
if ( ((i + 1) % 4) == 0) {
resultstr += x.substring(i, i + 1) + "|";
} else {
resultstr += x.substring(i, i + 1) + ",";
}
}
i++;
}
return resultstr;
}
Haven't got Java installed but tested the concept via PHP-code:
function matrixFormatter($x) {
$resultstr = "";
$i = 0;
while($i < strlen($x)) {
if ($i == strlen($x) - 1) {
$resultstr .= $x[$i];
} else {
if ( (($i + 1) % 4) == 0) {
$resultstr .= $x[$i] . "|";
} else {
$resultstr .= $x[$i] . ",";
}
}
$i++;
}
return $resultstr;
}
matrixFormatter("abcdefghijklmnopq") returns "a,b,c,d|e,f,g,h|i,j,k,l|m,n,o,p|q".
I'm not sure I understand you question correctly, you should probably add some input and expected output to be more clearer.
String a = "abcdefghijklmnop";
String a2 = "";
for (int i = 0; i < a.length(); i++) {
if (i != 0) {
if(i % 4 == 0){
a2 += "|";
} else{
a2 += ",";
}
}
a2 += a.charAt(i);
}
System.out.println(a2);
This will produce the output a,b,c,d|e,f,g,h|i,j,k,l|m,n,o,p
I want to print every possible combinations by using given letters without change letter orders so i wrote this code but it will print every line again and again what is the problem
public class Solutions {
public static void main(String[] args) {
// Scanner scanner = new Scanner(System.in);
c = "l u k".split(" ");
Solutions solutions = new Solutions();
solutions.combi(0);
System.out.println("Number of combi = " + count);
System.out.print(max);
}
static String[] c;
static int count = 0;
static int max = 0;
public void combi(int start) {
int j;
if (start != 0) {
String str = "";
for (int i = 0; i < start; i++) {
// System.out.print(c[i]);
str += c[i];
}
// System.out.println();
count++;
}
for (j = start; j < c.length; j++) {
combi(start + 1);
}
}
}
public void combi(int start) {
int j;
if (start != 0) {
for (int i = 0; i < start; i++) {
System.out.print(c[i]);
}
System.out.println();
count++;
} else {
for (j = start+1; j <= c.length; j++) {
combi(j);
}
}
}
I am struggling with a "find supersequence" algorithm.
The input is for set of strings
String A = "caagccacctacatca";
String B = "cgagccatccgtaaagttg";
String C = "agaacctgctaaatgctaga";
the result would be properly aligned set of strings (and next step should be merge)
String E = "ca ag cca cc ta cat c a";
String F = "c gag ccat ccgtaaa g tt g";
String G = " aga acc tgc taaatgc t a ga";
Thank you for any advice (I am sitting on this task for more than a day)
after merge the superstring would be
cagagaccatgccgtaaatgcattacga
The definition of supersequence in "this case" would be something like
The string R is contained in supersequence S if and only if all characters in a string R are present in supersequence S in the order in which they occur in the input sequence R.
The "solution" i tried (and again its the wrong way of doing it) is:
public class Solution4
{
static boolean[][] map = null;
static int size = 0;
public static void main(String[] args)
{
String A = "caagccacctacatca";
String B = "cgagccatccgtaaagttg";
String C = "agaacctgctaaatgctaga";
Stack data = new Stack();
data.push(A);
data.push(B);
data.push(C);
Stack clone1 = data.clone();
Stack clone2 = data.clone();
int length = 26;
size = max_size(data);
System.out.println(size+" "+length);
map = new boolean[26][size];
char[] result = new char[size];
HashSet<String> chunks = new HashSet<String>();
while(!clone1.isEmpty())
{
String a = clone1.pop();
char[] residue = make_residue(a);
System.out.println("---");
System.out.println("OLD : "+a);
System.out.println("RESIDUE : "+String.valueOf(residue));
String[] r = String.valueOf(residue).split(" ");
for(int i=0; i<r.length; i++)
{
if(r[i].equals(" ")) continue;
//chunks.add(spaces.substring(0,i)+r[i]);
chunks.add(r[i]);
}
}
for(String chunk : chunks)
{
System.out.println("CHUNK : "+chunk);
}
}
static char[] make_residue(String candidate)
{
char[] result = new char[size];
for(int i=0; i<candidate.length(); i++)
{
int pos = find_position_for(candidate.charAt(i),i);
for(int j=i; j<pos; j++) result[j]=' ';
if(pos==-1) result[candidate.length()-1] = candidate.charAt(i);
else result[pos] = candidate.charAt(i);
}
return result;
}
static int find_position_for(char character, int offset)
{
character-=((int)'a');
for(int i=offset; i<size; i++)
{
// System.out.println("checking "+String.valueOf((char)(character+((int)'a')))+" at "+i);
if(!map[character][i])
{
map[character][i]=true;
return i;
}
}
return -1;
}
static String move_right(String a, int from)
{
return a.substring(0, from)+" "+a.substring(from);
}
static boolean taken(int character, int position)
{ return map[character][position]; }
static void take(char character, int position)
{
//System.out.println("taking "+String.valueOf(character)+" at "+position+" (char_index-"+(character-((int)'a'))+")");
map[character-((int)'a')][position]=true;
}
static int max_size(Stack stack)
{
int max=0;
while(!stack.isEmpty())
{
String s = stack.pop();
if(s.length()>max) max=s.length();
}
return max;
}
}
Finding any common supersequence is not a difficult task:
In your example possible solution would be something like:
public class SuperSequenceTest {
public static void main(String[] args) {
String A = "caagccacctacatca";
String B = "cgagccatccgtaaagttg";
String C = "agaacctgctaaatgctaga";
int iA = 0;
int iB = 0;
int iC = 0;
char[] a = A.toCharArray();
char[] b = B.toCharArray();
char[] c = C.toCharArray();
StringBuilder sb = new StringBuilder();
while (iA < a.length || iB < b.length || iC < c.length) {
if (iA < a.length && iB < b.length && iC < c.length && (a[iA] == b[iB]) && (a[iA] == c[iC])) {
sb.append(a[iA]);
iA++;
iB++;
iC++;
}
else if (iA < a.length && iB < b.length && a[iA] == b[iB]) {
sb.append(a[iA]);
iA++;
iB++;
}
else if (iA < a.length && iC < c.length && a[iA] == c[iC]) {
sb.append(a[iA]);
iA++;
iC++;
}
else if (iB < b.length && iC < c.length && b[iB] == c[iC]) {
sb.append(b[iB]);
iB++;
iC++;
} else {
if (iC < c.length) {
sb.append(c[iC]);
iC++;
}
else if (iB < b.length) {
sb.append(b[iB]);
iB++;
} else if (iA < a.length) {
sb.append(a[iA]);
iA++;
}
}
}
System.out.println("SUPERSEQUENCE " + sb.toString());
}
}
However the real problem to solve is to find the solution for the known problem of Shortest Common Supersequence http://en.wikipedia.org/wiki/Shortest_common_supersequence,
which is not that easy.
There is a lot of researches which concern the topic.
See for instance:
http://www.csd.uwo.ca/~lila/pdfs/Towards%20a%20DNA%20solution%20to%20the%20Shortest%20Common%20Superstring%20Problem.pdf
http://www.ncbi.nlm.nih.gov/pubmed/14534185
You can try finding the shortest combination like this
static final char[] CHARS = "acgt".toCharArray();
public static void main(String[] ignored) {
String A = "caagccacctacatca";
String B = "cgagccatccgtaaagttg";
String C = "agaacctgctaaatgctaga";
String expected = "cagagaccatgccgtaaatgcattacga";
List<String> ABC = new Combination(A, B, C).findShortest();
System.out.println("expected: " + expected.length());
System.out.println("Merged: " + ABC.get(0).length() + " " + ABC);
}
static class Combination {
int shortest = Integer.MAX_VALUE;
List<String> shortestStr = new ArrayList<>();
char[][] chars;
int[] pos;
int count = 0;
Combination(String... strs) {
chars = new char[strs.length][];
pos = new int[strs.length];
for (int i = 0; i < strs.length; i++) {
chars[i] = strs[i].toCharArray();
}
}
public List<String> findShortest() {
findShortest0(new StringBuilder(), pos);
return shortestStr;
}
private void findShortest0(StringBuilder sb, int[] pos) {
if (allDone(pos)) {
if (sb.length() < shortest) {
shortestStr.clear();
shortest = sb.length();
}
if (sb.length() <= shortest)
shortestStr.add(sb.toString());
count++;
if (++count % 100 == 1)
System.out.println("Searched " + count + " shortest " + shortest);
return;
}
if (sb.length() + maxLeft(pos) > shortest)
return;
int[] pos2 = new int[pos.length];
int i = sb.length();
sb.append(' ');
for (char c : CHARS) {
if (!tryChar(pos, pos2, c)) continue;
sb.setCharAt(i, c);
findShortest0(sb, pos2);
}
sb.setLength(i);
}
private int maxLeft(int[] pos) {
int maxLeft = 0;
for (int i = 0; i < pos.length; i++) {
int left = chars[i].length - pos[i];
if (left > maxLeft)
maxLeft = left;
}
return maxLeft;
}
private boolean allDone(int[] pos) {
for (int i = 0; i < chars.length; i++)
if (pos[i] < chars[i].length)
return false;
return true;
}
private boolean tryChar(int[] pos, int[] pos2, char c) {
boolean matched = false;
for (int i = 0; i < chars.length; i++) {
pos2[i] = pos[i];
if (pos[i] >= chars[i].length) continue;
if (chars[i][pos[i]] == c) {
pos2[i]++;
matched = true;
}
}
return matched;
}
}
prints many solutions which are shorter than the one suggested.
expected: 28
Merged: 27 [acgaagccatccgctaaatgctatcga, acgaagccatccgctaaatgctatgca, acgaagccatccgctaacagtgctaga, acgaagccatccgctaacatgctatga, acgaagccatccgctaacatgcttaga, acgaagccatccgctaacatgtctaga, acgaagccatccgctacaagtgctaga, acgaagccatccgctacaatgctatga, acgaagccatccgctacaatgcttaga, acgaagccatccgctacaatgtctaga, acgaagccatcgcgtaaatgctatcga, acgaagccatcgcgtaaatgctatgca, acgaagccatcgcgtaacagtgctaga, acgaagccatcgcgtaacatgctatga, acgaagccatcgcgtaacatgcttaga, acgaagccatcgcgtaacatgtctaga, acgaagccatcgcgtacaagtgctaga, acgaagccatcgcgtacaatgctatga, acgaagccatcgcgtacaatgcttaga, acgaagccatcgcgtacaatgtctaga, acgaagccatgccgtaaatgctatcga, acgaagccatgccgtaaatgctatgca, acgaagccatgccgtaacagtgctaga, acgaagccatgccgtaacatgctatga, acgaagccatgccgtaacatgcttaga, acgaagccatgccgtaacatgtctaga, acgaagccatgccgtacaagtgctaga, acgaagccatgccgtacaatgctatga, acgaagccatgccgtacaatgcttaga, acgaagccatgccgtacaatgtctaga, cagaagccatccgctaaatgctatcga, cagaagccatccgctaaatgctatgca, cagaagccatccgctaacagtgctaga, cagaagccatccgctaacatgctatga, cagaagccatccgctaacatgcttaga, cagaagccatccgctaacatgtctaga, cagaagccatccgctacaagtgctaga, cagaagccatccgctacaatgctatga, cagaagccatccgctacaatgcttaga, cagaagccatccgctacaatgtctaga, cagaagccatcgcgtaaatgctatcga, cagaagccatcgcgtaaatgctatgca, cagaagccatcgcgtaacagtgctaga, cagaagccatcgcgtaacatgctatga, cagaagccatcgcgtaacatgcttaga, cagaagccatcgcgtaacatgtctaga, cagaagccatcgcgtacaagtgctaga, cagaagccatcgcgtacaatgctatga, cagaagccatcgcgtacaatgcttaga, cagaagccatcgcgtacaatgtctaga, cagaagccatgccgtaaatgctatcga, cagaagccatgccgtaaatgctatgca, cagaagccatgccgtaacagtgctaga, cagaagccatgccgtaacatgctatga, cagaagccatgccgtaacatgcttaga, cagaagccatgccgtaacatgtctaga, cagaagccatgccgtacaagtgctaga, cagaagccatgccgtacaatgctatga, cagaagccatgccgtacaatgcttaga, cagaagccatgccgtacaatgtctaga, cagagaccatccgctaaatgctatcga, cagagaccatccgctaaatgctatgca, cagagaccatccgctaacagtgctaga, cagagaccatccgctaacatgctatga, cagagaccatccgctaacatgcttaga, cagagaccatccgctaacatgtctaga, cagagaccatccgctacaagtgctaga, cagagaccatccgctacaatgctatga, cagagaccatccgctacaatgcttaga, cagagaccatccgctacaatgtctaga, cagagaccatcgcgtaaatgctatcga, cagagaccatcgcgtaaatgctatgca, cagagaccatcgcgtaacagtgctaga, cagagaccatcgcgtaacatgctatga, cagagaccatcgcgtaacatgcttaga, cagagaccatcgcgtaacatgtctaga, cagagaccatcgcgtacaagtgctaga, cagagaccatcgcgtacaatgctatga, cagagaccatcgcgtacaatgcttaga, cagagaccatcgcgtacaatgtctaga, cagagaccatgccgtaaatgctatcga, cagagaccatgccgtaaatgctatgca, cagagaccatgccgtaacagtgctaga, cagagaccatgccgtaacatgctatga, cagagaccatgccgtaacatgcttaga, cagagaccatgccgtaacatgtctaga, cagagaccatgccgtacaagtgctaga, cagagaccatgccgtacaatgctatga, cagagaccatgccgtacaatgcttaga, cagagaccatgccgtacaatgtctaga, cagagccatcctagctaaagtgctaga, cagagccatcctagctaaatgctatga, cagagccatcctagctaaatgcttaga, cagagccatcctagctaaatgtctaga, cagagccatcctgactaaagtgctaga, cagagccatcctgactaaatgctatga, cagagccatcctgactaaatgcttaga, cagagccatcctgactaaatgtctaga, cagagccatcctgctaaatgctatcga, cagagccatcctgctaaatgctatgca, cagagccatcctgctaacagtgctaga, cagagccatcctgctaacatgctatga, cagagccatcctgctaacatgcttaga, cagagccatcctgctaacatgtctaga, cagagccatcctgctacaagtgctaga, cagagccatcctgctacaatgctatga, cagagccatcctgctacaatgcttaga, cagagccatcctgctacaatgtctaga]