283. Move Zeroes

Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements.

For example, given nums = [0, 1, 0, 3, 12], after calling your function, nums should be [1, 3, 12, 0, 0].

Note:

1. You must do this in-place without making a copy of the array.
2. Minimize the total number of operations.

Credits:
Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases.

这道题的思路很简单, O(n) 遍历的过程中，统计0的个数n，当前元素为零，则统计n加一，若不为零，则将元素提前n个位置，最后在数组末尾填补n个0。

代码如下：

public class Solution {    public void moveZeroes(int[] nums) {        int i = 0, n  = 0;        while(i < nums.length) {            if(nums[i] == 0) {                n ++;            } else {                nums[i - n] = nums[i];            }            i ++;        }        i = 0;        while (i < n) {            nums[nums.length - 1 -i] = 0;            i ++;        }    }}

这道题 java 的时间略胜一筹，比 c 和 c++还快一点。