The XOR Problem (Hack The Interview V : Asia-Pacific)

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import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'maxXorValue' function below.
     *
     * The function is expected to return a STRING.
     * The function accepts following parameters:
     *  1. STRING x
     *  2. INTEGER k
     */

    public static String maxXorValue(String x, int k) {
        StringBuilder s = new StringBuilder();
        int n = 0;
        int i = 0;
        for(i=0;i<x.length();i++){
            if(n<k){
                if(x.charAt(i)=='0'){
                    s.append('1');
                    n += 1;
                }
                else{
                    s.append('0');
                }
            }
        }
        for(int j=s.length();j<x.length();j++){
            s.append("0");
        }
        return String.valueOf(s);
    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        int t = Integer.parseInt(bufferedReader.readLine().trim());

        IntStream.range(0, t).forEach(tItr -> {
            try {
                String s = bufferedReader.readLine();

                int k = Integer.parseInt(bufferedReader.readLine().trim());

                String y = Result.maxXorValue(s, k);

                bufferedWriter.write(y);
                bufferedWriter.newLine();
            } catch (IOException ex) {
                throw new RuntimeException(ex);
            }
        });

        bufferedReader.close();
        bufferedWriter.close();
    }
}