Move Zeroes

Description

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.

Example:

Input: [0,1,0,3,12]
Output: [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.

Solution(javascript)

/*
 * @lc app=leetcode id=283 lang=javascript
 *
 * [283] Move Zeroes
 */

// @lc code=start
// /** 1: O(N)
//  * @param {number[]} nums
//  * @return {void} Do not return anything, modify nums in-place instead.
//  */
// const moveZeroes = function (nums) {
//   let right = 0
//   for (let i = 0; i < nums.length; i++) {
//     if (nums[i] === 0) {
//       right = Math.max(i + 1, right + 1)
//       while (nums[right] === 0 && right < nums.length) {
//         right++
//       }
//       if (right < nums.length) {
//         nums[i] = nums[right]
//         nums[right] = 0
//       } else {
//         break
//       }
//     }
//   }
// }

/** 2: O(N)
 * 把不是 0 的元素往前移动
 * @param {number[]} nums
 * @return {void} Do not return anything, modify nums in-place instead.
 */
const moveZeroes = function (nums) {
  let index = 0
  for (const num of nums) {
    if (num !== 0) {
      nums[index++] = num
    }
  }
  while (index < nums.length) {
    nums[index++] = 0
  }
}
// @lc code=end