FZU 1502 Letter Deletion

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-8;
void File()
{
    freopen("D:\\in.txt","r",stdin);
    freopen("D:\\out.txt","w",stdout);
}
inline int read()
{
    char c = getchar();  while(!isdigit(c)) c = getchar();
    int x = 0;
    while(isdigit(c)) { x = x * 10 + c - ‘0‘; c = getchar(); }
    return x;
}

const int maxn=1000;
char s[maxn],t[maxn];
int dp[maxn][maxn];

int main()
{
    while(~scanf("%s%s",s,t))
    {
        memset(dp,0,sizeof dp);
        int lens=strlen(s),lent=strlen(t),ans=0;
        for(int i=0;i<lens;i++)
        {
            for(int j=0;j<lent;j++)
            {
                if(s[i]==t[j]) dp[i+1][j+1]=dp[i][j]+1;
                else dp[i+1][j+1]=max(dp[i][j+1],dp[i+1][j]);
                ans=max(dp[i+1][j+1],ans);
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}