经典动态规划

由于牛客网的编译器不支持用变量作为数组维数，改用二维vector替代动态数组。

#include <iostream>
#include <vector>
using namespace std;
int main()
{
    auto result = 0;
    string s1;
    string s2;
    cin >> s1;
    cin >> s2;
    int len1 = s1.length() + 1;
    int len2 = s2.length() + 1;

    vector<vector<int>> dp = vector<vector<int>>(len2, vector<int>(len1, 0));

    int i = 1, j = 1;
    for (i = 1; i < len2; ++i) {
        for(j = 1; j < len1; j++) {
            if (s2[i - 1] == s1[j - 1])
            {
                dp[i][j] = dp[i -1][j - 1] + 1;
                result = max (result, dp[i][j]);
            }
        }
    }
    cout << result << endl;
    return 0;
}