题解 | #最长公共子串#

class Solution {
public:
    /**
     * longest common substring
     * @param str1 string字符串 the string
     * @param str2 string字符串 the string
     * @return string字符串
     */
    string LCS(string str1, string str2) {
        int n = str1.size();
        int m = str2.size();
        vector<vector<int>> dp(n+1,vector<int>(m+1,0));
        int max = 0,index = -1;
        for(int i = 1;i <= n;i++){
            for(int j = 1;j <= m;j++){
                if(str1[i - 1] == str2[j - 1]){
                    dp[i][j] = dp[i-1][j-1] + 1;
                    if(max < dp[i][j]){
                    max = dp[i][j];
                    index = i;
                    }
                }
            }
        }
        return str1.substr(index - max,max);
    }
};