原文：
Write an algorithm such that if an element in an MxN matrix is 0,its entire row and column is set to 0.
译文：
写一个函数处理一个MxN的矩阵，如果矩阵中某个元素为0，那么把它所在的行和列都置为0.
解答：这道题有一个陷阱，如果在遍历矩阵的过程中遇到0就处理，就会出现问题。所以处理手段是：先记录0出现的位置，然后集中处理0所在行所在列着非常重要。
package com.zhuyu_deng.test;
public class Test
{
public static void main(String args[])
{
final int N = 10;
int cnt = 1;
int arr[][] = new int[N][N];
for (int i = 0; i < N; ++i)
{
for (int j = 0; j < N; ++j)
{
arr[i][j] = cnt++;
}
}
arr[5][6] = 0;
handleMatrix(arr);
for (int i = 0; i < N; ++i)
{
for (int j = 0; j < N; ++j)
{
System.out.print(arr[i][j] + " ");
}
System.out.println();
}
}
private static void handleMatrix(int[][] arr)
{
boolean row[] = new boolean[arr.length];
boolean col[] = new boolean[arr.length];
for (int i = 0; i < arr.length; ++i)
{
for (int j = 0; j < arr[i].length; ++j)
{
if (arr[i][j] == 0)
{
row[i] = true;
col[j] = true;
}
}
}
for (int i = 0; i < arr.length; ++i)
{
for (int j = 0; j < arr.length; ++j)
if (row[i] || col[j])
arr[i][j] = 0;
}
}
}