CareerCup_1_7

Write an algorithm such that if an element in an MxN matrix is 0, its entire row and column are set to 0.

/*
Write an algorithm such that if an element in an MxN matrix is 0,
its entire row and column are set to 0.
*/

const int MAX_INT = 0x7FFFFFFF;

void SetMatrixZero(int **matrix, int row, int col);
void SetMatrixZero2(int **matrix, int row, int col);

void TestSetMatrixZero();

void PrintMatrix2(int **matrix, int row, int col);

#include <iostream>

#include "1_7_SetMatrixZero.h"

using namespace std;

void SetMatrixZero(int **matrix, int row, int col)
{
for (int i = 0; i < row; ++i)
{
for (int j = 0; j < col; ++j)
{
if (matrix[i][j] == 0)
{
matrix[i][j] = MAX_INT;
}
}
}
for (int i = 0; i < row; ++i)
{
for (int j = 0; j < col; ++j)
{
if (matrix[i][j] == MAX_INT)
{
// the same row
for (int k = 0; k < col; ++k)
{
if (matrix[i][k] != MAX_INT)
{
matrix[i][k] = 0;
}
}
// the same col
for (int k = 0; k < row; ++k)
{
if (matrix[k][j] != MAX_INT)
{
matrix[k][j] = 0;
}
}
matrix[i][j] = 0;
}
}
}
}

void TestSetMatrixZero()
{
int row = 4;
int col = 3;

int **matrix = new int *[4];
for (int i = 0; i < row; ++i)
{
matrix[i]= new int[3];
}

for (int i = 0; i < row; ++i)
{
for (int j = 0; j < col; ++j)
{
matrix[i][j] = i + j + 1;
}
}

matrix[1][1] = 0;
//matrix[2][2] = 0;

PrintMatrix2(matrix, 4, 3);
SetMatrixZero2(matrix, 4, 3);
PrintMatrix2(matrix, 4, 3);

for (int i = 0; i < row; ++i)
{
delete []matrix[i];
}
delete[] matrix;
}

void PrintMatrix2(int **matrix, int row, int col)
{
for (int i = 0; i < row; ++i)
{
for (int j = 0; j < col; ++j)
{
printf("%4d", matrix[i][j]);
}
cout << endl;
}
cout << endl;
}

void SetMatrixZero2(int **matrix, int row, int col)
{
bool *rowFlag = new bool[row];
bool *colFlag = new bool[col];
memset(rowFlag, 0, sizeof(bool) * row);
memset(colFlag, 0, sizeof(bool) * col);
for (int i = 0; i < row; ++i)
{
for (int j = 0; j < col; ++j)
{
if (matrix[i][j] == 0)
{
rowFlag[i] = true;
colFlag[j] = true;
}
}
}
for (int i = 0; i < row; ++i)
{
if (rowFlag[i])
{
for (int k = 0; k < col; ++k)
{
matrix[i][k] = 0;
}
}
}
for (int i = 0; i < col; ++i)
{
if (colFlag[i])
{
for (int k = 0; k < row; ++k)
{
matrix[k][i] = 0;
}
}
}
delete[]rowFlag;
delete[]colFlag;
}