问题标题: 酷町堂：1290 糖果盒（candybox）：90分

#include<iostream>
using namespace std;
int n,m,a[301][301],s[301][301],f[301][301],f1[301][301],ans;
int main()
{
    cin>>n>>m;
    for(int i=1;i<=n;i++)
    for(int j=1;j<=m;j++)
    {
        cin>>a[i][j];
        if(a[i][j]==0)a[i][j]=-100000000;
        s[i][j]=s[i][j-1]+a[i][j];
    }
    for(int i=1;i<=m;i++)
    for(int j=i+1;j<=m;j++)
    for(int k=1;k<=n;k++){
        f1[i][j]=max(f1[i][j],0)+s[k][j]-s[k][i-1];
        f[i][j]=max(f[i][j],f1[i][j]);
    }
    for(int i=1;i<=n;i++)
    for(int j=1;j<=m;j++)
    ans=max(ans,f[i][j]); 
    cout<<ans;
    return 0;
}