[UVa] 836 Largest Submatrix.cpp

#include <iostream>
#include <string>
using namespace std;

string Matrix[1000];
bool is1(int i, int i_end, int j);

int main()
{
    ios::sync_with_stdio(false);
    int Case;
    cin >> Case;
    while (Case--)
    {
        cin >> Matrix[0];
        int N = Matrix[0].size();

        for (int i = 1; i < N; ++i)
            cin >> Matrix[i];

        int MSS = 0, Max = 0;
        for (int Len = 1; Len <= N; ++Len) {
            for (int i = 0; i + Len - 1 < N; ++i) {
                MSS = 0;
                for (int j = 0; j < N; ++j) {
                    if (is1(i, i+Len-1, j))
                        MSS += Len;
                    else
                        MSS = 0;

                    if (MSS > Max) Max = MSS;
                }
            }
        }
        cout << Max << endl;
        if (Case) cout << endl;
    }
}
bool is1(int i, int i_end, int j)
{
    for (i; i <= i_end; ++i)
        if (Matrix[i][j] != '1')
            return false;
    return true;
}