poj 1050 To the Max_dp求最大子矩阵和

题意：求最大子矩阵和

利用dp[i]每次向下更新，构成竖起的单条矩阵，再按不小于零就加起来来更新，构成更大的矩阵

#include <iostream>#include<cstdio>#include<cstring> using namespace std;#define N 110int map[N][N],dp[N];int main(int argc, char** argv) {int n,i,j,k,maxn,ans;while(scanf("%d",&n)!=EOF){ans=-9999999;for(i=0;i<n;i++)for(j=0;j<n;j++)scanf("%d",&map[i][j]);for(i=0;i<n;i++){memset(dp,0,sizeof(dp));for(j=i;j<n;j++){for(k=0;k<n;k++){dp[k]+=map[j][k];}maxn=-1;for(k=0;k<n;k++){maxn=maxn<0?dp[k]:maxn+dp[k];if(maxn>ans)ans=maxn;}}}printf("%d\n",ans);}return 0;}