poj 1050 To the Max

#include<iostream>
#include<string.h>
#include<math.h>
#include<fstream>
#include<algorithm>
#include<stdio.h>
#include<queue>
#include<vector>
#define MAXSIZE 100
using namespace std;
int n = 0, dat[201][201];
int rec[201];
int maxn = 0;
int dp[201][128];
int main()
{
//freopen("data_1050.txt","r",stdin);
char s[201];
while(scanf("%d", &n) != EOF)
{
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
scanf("%d", &dat[i][j]);
if (maxn < dat[i][j])
{
maxn = dat[i][j];
}
}
}
memset(dp, 0, sizeof(dp));
for (int i = 0; i < n; i++)
{
memset(rec, 0, sizeof(rec));
for (int j = i; j < n; j++)
{
for (int k = 0; k < n; k++)
{
rec[k] += dat[j][k];
}
int sum = 0;
for (int l = 0; l < n; l++)
{
if (sum > 0)
{
sum += rec[l];
}else
{
sum = rec[l];
}
if (sum > maxn)
{
maxn = sum;
}
}
}
}
printf("%d\n", maxn);
}

return 0;
}