[LeetCode][JavaScript]Move Zeroes

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.

https://leetcode.com/problems/move-zeroes/

把数组中所有的零放到最后，不能简单地再开一个数组。

第一种优雅的做法，开一个变量count=0，把数组中不为零的数，按顺序移动到下标为count的位置上，每移动一个count++，最后补上0。

/**
* @param {number[]} nums
* @return {void} Do not return anything, modify nums in-place instead.
*/
var moveZeroes = function(nums) {
var count = 0;
for(var i = 0; i < nums.length; i++){
if(nums[i] !== 0){
nums[count] = nums[i];
count++;
}
}
for(; count < nums.length ; count++){
nums[count] = 0;
}
};

第二种调用了强大的splice方法，先记录下0的位置，从后往前把0从数组中删掉（从前往后会打乱下标的顺序），最后再补齐。

/**
* @param {number[]} nums
* @return {void} Do not return anything, modify nums in-place instead.
*/
var moveZeroes = function(nums) {
var indexArr = [], i;
for(i = 0; i < nums.length; i++){
if(nums[i] === 0){
indexArr.push(i);
}
}
for(i = indexArr.length - 1; i >= 0; i--){
nums.splice(indexArr[i], 1);
}
for(i = 0; i < indexArr.length; i++){
nums.push(0);
}
};