题目出处：https://leetcode-cn.com/problems/longest-common-subsequence/

dp[i][j]：代表是s1[0:i] 与 s2[0:j] 字符串的最长公共子串的长度。

class Solution {
public:
    int longestCommonSubsequence(string text1, string text2) {
        int m = text1.length();
        int n = text2.length();
        vector<vector<int>> dp(m+1, vector<int>(n+1, 0));
        for(int i = 1; i <= m; i++){
            for(int j = 1; j <= n; j++){
                if(text1[i-1] == text2[j-1]){
                    dp[i][j] = dp[i-1][j-1] + 1;
                }  
                else{
                    dp[i][j] = max(dp[i-1][j], dp[i][j-1]);
                }
            }
        }
        return dp[m][n];
    }
};```