Cracking The Coding Interview 1.7

//Write an algorithm such that if an element in an MxN matrix is 0, its entire row and column is set to 0.
//
//这题原答案就是要两个buffer来记录出现0的位置。不知道有没可以不用buffer的方法。

#include <iostream>
using namespace std;
void setZero(int **matrix, int m, int n)
{
	int *hang = new int[n];
	int *lie = new int[m];
	for (int i = 0; i< m; i++)
	{
		for (int j=0; j <n;j++)
		{
			if (matrix[i][j] == 0)
			{
				hang[j] = 1;
				lie[i] = 1;
			}
		}
	}
	for (int i = 0; i<m; i++)
	{
		for (int j = 0; j<n; j++)
		{
			if (hang[j] ==1 || lie[i] ==1)
			{
				matrix[i][j]=0;
			}
		}
	}
}

void display(int **matrix, int size, int n)
{
	for (int k = 0; k<size; k++)
		for (int t = 0; t<n; t++)
		{
			cout<<matrix[k][t]<<"  ";
			if (t==n-1)
			{
				cout<<endl;
			}
		}
}

int main()
{
	int m = 4,n = 5;
	int **p = new int *[m];
	for (int i=0;i<m;i++)
	{
		p[i] = new int[n];
	}
	
	for (int i =0;i<m;i++)
	{
		for (int j=0;j<n;j++)
		{
			p[i][j] = 2*i+j; 
		}
	}
	p[2][3] =0;
	display(p,m,n);
	cout<<endl;
	setZero(p,m,n);
	display(p,m,n);
	return 0;
}