hdu 1081 To The Max

http://acm.hdu.edu.cn/showproblem.php?pid=1081

#include <cstdio>
#include <cstring>
#include <algorithm>
#define maxn 300
using namespace std;
const int inf=0x7fffffff;

int dp[maxn][maxn];
int a[maxn][maxn];

int main()
{
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        for(int i=1; i<=n; i++)
        {
            dp[i][0]=0;
            for(int j=1; j<=n; j++)
            {
                scanf("%d",&a[i][j]);
                dp[i][j]=dp[i][j-1]+a[i][j];
            }
        }
        int max1=-inf;
        for(int i=1; i<=n; i++)
        {
            for(int j=1; j<=i; j++)
            {
                int c=0;
                for(int k=1; k<=n; k++)
                {
                    c+=(dp[k][i]-dp[k][j-1]);
                    if(max1<c)
                        max1=c;
                    if(c<0)
                        c=0;
                }
            }
        }
        printf("%d
",max1);
    }
    return 0;
}