HDU 1081 To The Max

 1 //#define LOCAL
 2 #include <iostream>
 3 #include <cstdio>
 4 #include <cstring>
 5 using namespace std;
 6 
 7 int dp[105], sum[105];
 8 int data[105][105];
 9 
10 int main(void)
11 {
12     #ifdef LOCAL
13         freopen("1081in.txt", "r", stdin);
14     #endif
15 
16     int n;
17     while(scanf("%d", &n) == 1)
18     {
19         int i, j, k;
20         int ans = -1000;
21         for(i = 0; i < n; ++i)
22             for(j = 0; j < n; ++j)
23                 scanf("%d", &data[i][j]);
24 
25         for(i = 0; i < n; ++i)
26         {
27             memset(sum, 0, sizeof(sum));
28             for(j = i; j < n; ++j)
29             {
30                 for(k = 0; k < n; ++k)
31                     sum[k] += data[j][k];
32                 dp[0] = sum[0];
33                 for(k = 1; k < n; ++k)
34                 {
35                     if(dp[k - 1] > 0)
36                         dp[k] = dp[k - 1] + sum[k];
37                     else
38                         dp[k] = sum[k];
39                     if(dp[k] > ans)
40                         ans = dp[k];
41                 }
42             }
43         }
44 
45         printf("%d\n", ans);
46     }
47     return 0;
48 }