Maximal Rectangle LeetCode

https://leetcode.com/problems/maximal-rectangle/description/

同学推荐此题。

不能放main函数。

数据有可能为空，涨姿势了。。。

P.S: data in https://github.com/stomakun/LeetCodeTestData

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define minv 1e-6
#define inf 1e9
#define pi 3.1415926536
#define nl 2.7182818284
const ll mod=1e9+7;//998244353
const int maxn=1e7+10;

class Solution {
public:
    char **str;
    int **a,*x,*y,g=0;
    vector<vector<char> >::iterator u;
    vector<char>::iterator v;
    vector<char> w;
    int maximalRectangle(vector<vector<char>>& matrix) {
        int n,m,i,j,sum;
        n=matrix.size();
        if (n==0)
            m=0;
        else
            m=matrix[0].size();

        str=new char*[n+1];
        for (i=0;i<=n;i++)
            str[i]=new char[m+1];

        a=new int*[n+1];
        for (i=0;i<=n;i++)
            a[i]=new int[m+1];
        x=new int[m+1];
        y=new int[m+1];
        for (u=matrix.begin(),i=1;u!=matrix.end();u++,i++)
        {
            w=*u;
            for (v=w.begin(),j=1;v!=w.end();v++,j++)
                str[i][j]=*v;
        }

        for (i=0;i<=n;i++)
            a[i][0]=0;
        for (j=0;j<=m;j++)
            a[0][j]=0;
        for (j=1;j<=m;j++)
            for (i=1;i<=n;i++)
                a[i][j]=(str[i][j]=='1')?a[i-1][j]+1:0;
        sum=0;
        for (i=1;i<=n;i++)
        {
            g=0;
            for (j=1;j<=m;j++)
                if (g==0 || a[i][j]>x[g])
                {
                    g++;
                    x[g]=a[i][j];
                    y[g]=j;
                }
                else
                {
                    while (g!=0 && a[i][j]<x[g])
                        sum=max(sum,(j-y[g])*x[g]),g--;
                    if (g==0 || a[i][j]!=x[g])
                        g++;
                    x[g]=a[i][j];
                }
            while (g!=0)
                sum=max(sum,(m+1-y[g])*x[g]),g--;
        }
        return sum;
    }
}sol;

/*
int main()
{
    vector<vector<char>> matrix;
    vector<char> ch;
    matrix.clear();

//    ch.clear();
//    ch.push_back('1');
//    ch.push_back('0');
//    ch.push_back('1');
//    ch.push_back('0');
//    ch.push_back('0');
//    matrix.push_back(ch);
//
//    ch.clear();
//    ch.push_back('1');
//    ch.push_back('0');
//    ch.push_back('1');
//    ch.push_back('1');
//    ch.push_back('1');
//    matrix.push_back(ch);
//
//    ch.clear();
//    ch.push_back('1');
//    ch.push_back('1');
//    ch.push_back('1');
//    ch.push_back('1');
//    ch.push_back('1');
//    matrix.push_back(ch);

//    ch.clear();
//    ch.push_back('1');
//    ch.push_back('0');
//    ch.push_back('0');
//    ch.push_back('1');
//    ch.push_back('0');
//    matrix.push_back(ch);

    cout<<sol.maximalRectangle(matrix);
    return 0;
}
*/