题解 | #最长公共子串#

class Solution {
  public:
    int maxLen = 0;
    int indexI;

    string LCS(string str1, string str2) {
        vector<vector<int>> dp(str1.length() + 1, vector<int>(str2.length() + 1, 0));
        for (int i = 1; i <= str1.length(); i++) {
            for (int j = 1; j <= str2.length(); j++) {
                if (str1[i - 1] == str2[j - 1])
                    dp[i][j] = dp[i - 1][j - 1] + 1;
                if (dp[i][j] > maxLen) {
                    maxLen = dp[i][j];
                    indexI = i - 1;
                }
            }
        }
        string s = "";
        for (int i = maxLen; i > 0; i--) {
            s = str1[indexI--] + s;
        }
        return s;
    }
};