SubmatrixSumMax

#include <bits/stdc++.h>
using namespace std;
int n,a[305][305],b[305][305],v[305];

void Citire()
{
    cin>>n;
    for(int i=1;i<= n;++i)
        for(int j=1;j<=n;++j)
            cin>>a[i][j];
}

void SumePartiale()
{
    for(int i=1;i<=n;++i)
        for(int j=1;j<=n;++j)
            b[i][j]=a[i][j]+b[i-1][j];
}

int SecSumMax(int v[],int n)
{
    int s,smax;
    s=smax=v[1];
    if(s<0)
        s=0;
    for(int i=2;i<=n;++i)
    {
        s+=v[i];
        if(s>smax)
            smax=s;
        if(s<0)
            s=0;
    }
    return smax;
}

void Solutie()
{
    int ssmax,suma;
    ssmax=-200000000;
    for(int i1=1;i1<=n;++i1)
        for(int i2=i1;i2<=n;++i2)
        {
            for(int j=1;j<=n;++j)
                v[j]=b[i2][j]-b[i1-1][j];
            suma=SecSumMax(v,n);
            ssmax=max(ssmax,suma);
        }
    cout<<ssmax;
}

int main()
{
    Citire();
    SumePartiale();
    Solutie();
    return 0;
}