DP || POJ 1458 Common Subsequence

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
#define SZ 1005
int dp[SZ][SZ];
int main()
{
    char s1[SZ], s2[SZ], tmp[SZ];
    s1[0] = s2[0] = ‘0‘;
    while(scanf("%s", s1 + 1) != EOF)
    {
        scanf(" %s", s2 + 1);
        memset(dp, 0, sizeof(dp));
        int len1 = strlen(s1);
        int len2 = strlen(s2);
        for(int i = 0; i <= len1; i++)
        {
            for(int j = 0; j <= len2; j++)
            {
                if(i == 0 || j == 0) dp[i][j] = 0;
                else if(s1[i] == s2[j]) dp[i][j] = dp[i - 1][j - 1] + 1;
                else dp[i][j] = max(dp[i - 1][j], dp[i][j - 1]);
            }
        }
        printf("%d\n", dp[len1][len2] - 1);
    }
    return 0;
}