poj 1050(DP)

最大子矩阵和。类似于子序列最大和。

 // File Name: 1050.cpp
 // Author: Missa_Chen
 // Created Time: 2013年06月22日 星期六 17时06分39秒

 #include <iostream>
 #include <string>
 #include <algorithm>
 #include <cstdio>
 #include <cstring>
 #include <cmath>
 #include <queue>
 #include <map>
 #include <stack>
 #include <set>
 #include <cstdlib>

 using namespace std;

 #define LL long long
 const int inf = 0x3f3f3f3f;
 const int maxn = ;
 int n;
 int sum[maxn][maxn];
 int main()
 {
     while (~scanf("%d",&n))
     {
         for (int i = ; i <= n; ++i)
             for (int j = ; j <= n; ++j)
                 scanf("%d", &sum[i][j]);
         for (int i = ; i <= n; ++i)
             sum[i][] = ;
         for (int i = ; i <= n; ++i)
             for (int j = ; j <= n; ++j)
                 sum[i][j] += sum[i][j - ];
         int ans = -inf;
         for (int i = ; i <= n; ++i)
             for (int j = i; j <= n; ++j)
             {
                 int tmp = -inf;
                 for (int k = ; k <= n; ++k)
                 {
                     if (tmp >= )
                         tmp += (sum[k][j] - sum[k][i - ]);
                     else
                         tmp = sum[k][j] - sum[k][i - ];
                     ans = max(ans, tmp);
                 }
             }
         printf("%d\n", ans);
     }
     return ;
 }