Java: 这里使用了char数组,也可以不用char数组,直接用String类的charAt()方法获取单个字符。

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String nums = scanner.nextLine();
        String s1 = scanner.nextLine();
        String s2 = scanner.nextLine();
        // 开始算法
        char[] c1 = s1.toCharArray();
        char[] c2 = s2.toCharArray();
        int[][] dp = new int[c1.length+1][c2.length+1];
        for (int i = 1; i <= c1.length; i++) {
            for (int j = 1; j <= c2.length; j++) {
                if (c1[i-1] == c2[j-1]) {
                    dp[i][j] = dp[i-1][j-1] + 1;
                } else {
                    dp[i][j] = Math.max(dp[i][j-1], dp[i-1][j]);
                }
            }
        }
        System.out.println(dp[c1.length][c2.length]);
    }
}