计蒜客 最长公共子序列（DP）

最长公共子序列

#include <iostream>
#include <string>
#include <cstring>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <vector>

using namespace std;

#define maxn 1005
int ans[maxn][maxn];

int longestCommonSubsequence(string A, string B)
{
    int m = A.size();
    int n = B.size();

    for(int i = 0; i <= m; ++i)
    {
        ans[i][0] = 0;
    }
    for(int i = 0; i <= n; ++i)
    {
        ans[0][i] = 0;
    }

    for(int i = 1; i <= m; ++i)
    {
        for(int j = 1; j <= n; ++j)
        {
            if(A[i-1] == B[j-1])
            {
                ans[i][j] = ans[i-1][j-1] + 1;
            }
            else
            {
                ans[i][j] = max(ans[i-1][j], ans[i][j-1]);
            }
        }
    }

    return ans[m][n];
}

int main()
{
    //freopen("data.in","r",stdin);
    ios::sync_with_stdio(false);

    string A;
    string B;
    cin >> A >> B;
    int res = longestCommonSubsequence(A, B);
    cout << res << endl;

    return 0;
}