uva 10827 - Red Huang

最大子矩陣限制長寬 O (n4)
//====================================================================||  
//                                                                    ||  
//                                                                    ||  
//                         作者 : GCA                               ||  
//                  6AE7EE02212D47DAD26C32C0FE829006                  ||  
//====================================================================||  
#include <iostream>  
#include <cstdio>  
#include <cstring>  
#include <algorithm>  
#include <cmath>  
#include <climits>  
#include <vector>  
#include <set>  
#include <map>  
#include <queue>  
#include <cctype>  
#include <utility>  
using namespace std;  
#ifdef ONLINE\_JUDGE  
#define ll "%lld"  
#else  
#define ll "%I64d"  
#endif  
typedef unsigned int uint;  
typedef long long int Int;  
#define Set(a,s) memset(a,s,sizeof(a))  
#define Write(w) freopen(w,"w",stdout)  
#define Read(r) freopen(r,"r",stdin)  
#define Pln() printf("\\n")  
#define I\_de(x,n)for(int i=0;i<n;i++)printf("%d ",x\[i\]);Pln()  
#define De(x)printf(#x"%d\\n",x)  
#define For(i,x)for(int i=0;i<x;i++)  
#define CON(x,y) x##y  
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\\  
    printf("%d ",dp\[htx\]\[hty\]);}Pln();}  
#define M 500  
#define PII pair<int,int\>  
#define PB push\_back  
#define oo INT\_MAX  
#define Set\_oo 0x3f  
#define Is\_debug true  
#define debug(...) if(Is\_debug)printf("DEBUG: "),printf(\_\_VA\_ARGS\_\_)  
#define FOR(it,c) for(\_\_typeof((c).begin()) it=(c).begin();it!=(c).end();it++)  
#define eps 1e-6  
bool xdy(double x,double y){return x>y+eps;}  
bool xddy(double x,double y){return x>y-eps;}  
bool xcy(double x,double y){return x<y-eps;}  
bool xcdy(double x,double y){return x<y+eps;}  
int min3(int x,int y,int z){  
    int tmp=min(x,y);  
    return min(tmp,z);  
}  
int max3(int x,int y,int z){  
    int tmp=max(x,y);  
    return max(tmp,z);  
}  
int test;  
int n,tn;  
int mz\[M\]\[M\];  
int sum\[M\];  
void solve(){  
    int mt=0;  
    for(int i=0;i<n;i++){  
        Set(sum,0);  
        for(int j=i;j<i+n;j++){  
            for(int k=0;k<tn;k++)sum\[k\]+=mz\[j\]\[k\];  
            int t=0;  
            for(int ii=0;ii<n;ii++){  
                t=0;  
                for(int jj=ii;jj<ii+n;jj++){  
                    t+=sum\[jj\];  
                    if(t<0)t=0;  
                    mt=max(mt,t);  
                }  
            }  
        }  
    }  
    printf("%d\\n",mt);  
}  
int main() {  
    ios\_base::sync\_with\_stdio(0);  
    scanf("%d",&test);  
    while(test--){  
        scanf("%d",&n);  
        for(int i=0;i<n;i++){  
            for(int j=0;j<n;j++){  
                scanf("%d",&mz\[i\]\[j\]);  
                mz\[i+n\]\[j\]=mz\[i\]\[j+n\]=mz\[i+n\]\[j+n\]=mz\[i\]\[j\];  
            }  
        }  
        tn=n+n;  
        solve();  
    }  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
}