poj 1458 Common Subsequence

#include <iostream>
#include <stdio.h>
#include <string.h>
using namespace std;
#define MAXV 1000

int same(int a,int b){
return a==b?1:0;
}

int max(int a,int b, int c){
if(a>=b && a>=c) return a;
if(b>=a && b>=c) return b;
return c;
}

int dp[MAXV][MAXV];
char s1[MAXV],s2[MAXV];

int main(){
int len1,len2,i,j;

while(scanf("%s %s",s1,s2)!=EOF){
memset(dp,0,sizeof(dp));

len1=strlen(s1);
len2=strlen(s2);

for(i=1;i<=len1;i++){
for(j=1;j<=len2;j++){
dp[i][j]=max( dp[i-1][j-1]+same(s1[i-1],s2[j-1]) , dp[i-1][j] , dp[i][j-1]);
}
}

printf("%d\n",dp[len1][len2]);
}
return 0;
}