Leetcode 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:

You must do this in-place without making a copy of the array.

Minimize the total number of operations.
这道题要注意，是in place，

public class Solution {
public void moveZeroes(int[] nums) {
if(nums.length<=1) return;
int first = 0;
int sec = 0;
while(sec<nums.length) {
//find first zero element
while(first<nums.length && nums[first] !=0) {
first++;
}
if(first == nums.length) return;
sec = first+1;
//find following first non-zero element
while(sec<nums.length && nums[sec] == 0){
sec++;
}
if(sec == nums.length) return;
swap(nums, first, sec);
}
}
public void swap(int[] nums, int i, int j) {
int temp = nums[i];
nums[i] = nums[j];
nums[j] = temp;
}
}

之后又想了一种方法。
与27. Remove Element 类似 https://leetcode.com/problems/remove-element/。 差别是把数组最后的元素置为0。

public class Solution {
public void moveZeroes(int[] nums) {
if(nums ==null|| nums.length == 0)
return;

int len = 0;
for(int i =0; i < nums.length; i++){
if(nums[i] != 0){
if(nums[len]!=nums[i])
nums[len]=nums[i];
len++;
}
}
// return len;
for(int i = len; i < nums.length; i++){
nums[i] = 0;
}
}
}