两下标指针解决覆盖子序列

一开始真的想得很复杂，联想到了覆盖子串问题用滑动窗口方法。看了评论区才恍然大悟，双指针去遍历就行了。

import java.io.*;
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] params = br.readLine().trim().split(" ");
        int n = Integer.parseInt(params[0]);
        int m = Integer.parseInt(params[1]);
        String S = br.readLine().trim();
        String T = br.readLine().trim();
        int j = 0;
        long indexSum = 0;
        for(int i = 0; i < n; i++){
            if(S.charAt(i) == T.charAt(j)){
                j++;
                indexSum += i + 1;
            }
        }
        if(j == T.length()){
            System.out.println("Yes");
            System.out.println(indexSum);
        }else{
            System.out.println("No");
        }
    }
}