问我正在解决下面的问题，但是所有的测试用例在java中都没有通过。

EN

1 <= n <= 10000

1 <= |chromosome| <100

1 <= |gene| < |chromosome|

4
12sd78f
sf
12345efd
1e3d
ijkfgds
jkf
1111456
116

YES
NO
YES
YES

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class solution {

private static String checkGem(String ch, String gem) {

    int prevIndex = 0;
    for(int n=0; n < gem.length(); n++) {
        if(ch.indexOf(gem.charAt(n), prevIndex)==-1) {
            return "NO";
        }
        else {
            prevIndex = ch.indexOf(gem.charAt(n), prevIndex);
        }
    }

    return "YES";
}
public static void main(String args[]) throws Exception {

    //Scanner sc = new Scanner(System.in);
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    String test = br.readLine();    

    int t = Integer.parseInt(test);

    for(int i=0; i<t; i++) {
        String ch = br.readLine();
        String gem = br.readLine();
        ch = ch.replaceAll("\\s","");
        gem =  gem.replaceAll("\\s","");
        String ans = checkGem(ch, gem);
        System.out.println(ans);
    }

    }
}