poj 1050(DP)
最大子矩阵和。类似于子序列最大和。
1 // File Name: 1050.cpp 2 // Author: Missa_Chen 3 // Created Time: 2013年06月22日 星期六 17时06分39秒 4 5 #include <iostream> 6 #include <string> 7 #include <algorithm> 8 #include <cstdio> 9 #include <cstring> 10 #include <cmath> 11 #include <queue> 12 #include <map> 13 #include <stack> 14 #include <set> 15 #include <cstdlib> 16 17 using namespace std; 18 19 #define LL long long 20 const int inf = 0x3f3f3f3f; 21 const int maxn = 101; 22 int n; 23 int sum[maxn][maxn]; 24 int main() 25 { 26 while (~scanf("%d",&n)) 27 { 28 for (int i = 1; i <= n; ++i) 29 for (int j = 1; j <= n; ++j) 30 scanf("%d", &sum[i][j]); 31 for (int i = 1; i <= n; ++i) 32 sum[i][0] = 0; 33 for (int i = 1; i <= n; ++i) 34 for (int j = 2; j <= n; ++j) 35 sum[i][j] += sum[i][j - 1]; 36 int ans = -inf; 37 for (int i = 1; i <= n; ++i) 38 for (int j = i; j <= n; ++j) 39 { 40 int tmp = -inf; 41 for (int k = 1; k <= n; ++k) 42 { 43 if (tmp >= 0) 44 tmp += (sum[k][j] - sum[k][i - 1]); 45 else 46 tmp = sum[k][j] - sum[k][i - 1]; 47 ans = max(ans, tmp); 48 } 49 } 50 printf("%d\n", ans); 51 } 52 return 0; 53 }
