URAL 1146 Maximum Sum 最大子矩阵和

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 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef unsigned long long ll;
 4 const int INF = 0x3f3f3f3f;
 5 const int M = 2e2+3;
 6 
 7 int n;
 8 int a[M][M];    // a[i][j] 表示从[i][0]到[i][j]的和
 9 int main()  {
10     while( ~scanf("%d", &n ) )  {
11         memset( a, 0, sizeof(a) );
12         for( int i=1; i<=n; i++ )   {
13             for( int j=1; j<=n; j++ )   {
14                 scanf("%d", &a[i][j] );
15                 a[i][j] += a[i][j-1];
16             }
17         }
18         int ret = -INF;
19         for( int i=1; i<=n; i++ )   {
20             for( int j=0; j<i; j++ )    {
21                 int sum = 0;
22                 for( int h=1; h<=n; h++ )   {
23                     sum += a[h][i] - a[h][j];
24                     ret = max( ret, sum );
25                     if( sum < 0 ) sum = 0;
26                 }
27             }
28         }
29         printf("%d\n", ret );
30     }
31     return 0;
32 }

 

posted @ 2015-08-17 14:20  TaoTaoCome  阅读(151)  评论(0)  编辑  收藏  举报