Solution in Java to Problem C. "Encrypted Password" from Arab Collegiate Programming Contest (ACPC) 2012.

password.java

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;


public class password {

  public static void main(String[] args) throws FileNotFoundException {
		
		Scanner scan = new Scanner(new File("password.in"));
		int cases = scan.nextInt();
		for(int qq = 0; qq < cases; qq++) {
			
			String str = scan.next();
			String pass = scan.next();
			
			int[] count = new int[26];
			int[] solution = new int[26];
			
			//get the character count of the solution
			for(int i = 0; i < pass.length(); i++)
				solution[pass.charAt(i) - 'a']++;
			
			//get character counts for the first part of the whole string
			for(int i = 0; i < pass.length(); i++)
				count[str.charAt(i) - 'a']++;
			
			//compare both arrays to see if character counts match
			if(checkMatch(count, solution)) {
				System.out.println("YES");
				continue; //if this is a solution, go to the next test case
			}
			else if(str.length() == pass.length()) {
				System.out.println("NO");
				continue;
			}
			
			//continue checking for the whole string for possible matches
			for(int i = pass.length(); i < str.length(); i++) {
				count[str.charAt(i - pass.length()) - 'a']--;
				count[str.charAt(i) - 'a']++;
				if(checkMatch(count, solution)) {
					System.out.println("YES");
					break;
				}
				else if(i == str.length() - 1)
					System.out.println("NO");
			}
		}

	}
	
	public static boolean checkMatch(int[] a, int[] b) {
		
		for(int i = 0; i < a.length; i++)
			if(a[i] != b[i])
				return false;
		return true;
	}

}