func_code_string: #include <bits/stdc++.h>   using namespace std;   int dirx[] = {1, -1, 0, 0, 1, 1, -1, -1}, diry[] = {0, 0, 1, -1, 1, -1, 1, -1};   bool Set(int n, int pos) { return bool(n & (1 << pos)); }   int32_t main() {     ios_base::sync_with_stdio(false);     int n, m;     cin >> n >> m;     string a, b;     cin >> a >> b;     int dp[n + 1][m + 1], ans = -1;     memset(dp, 0, sizeof(dp));     for (int i = 1; i <= n; i++) {       for (int j = 1; j <= m; j++) {         dp[i][j] = max(0, max(dp[i - 1][j], dp[i][j - 1]) - 1);         if (a[i - 1] == b[j - 1]) dp[i][j] = max(dp[i][j], dp[i - 1][j - 1] + 2);         ans = max(ans, dp[i][j]);       }     }     cout << ans;     return 0;   }   