LeetCode 283 Move Zeroes 移动零

题目描述

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

Note that you must do this in-place without making a copy of the array.

Example 1:

Input: nums = [0,1,0,3,12]
Output: [1,3,12,0,0]
Example 2:

Input: nums = [0]
Output: [0]

题解

/**
 * 快慢指针
 * 快指针用于遍历数组
 * 慢指针用于指向下一个被替换/覆盖的元素，即0元素
 * @param {number[]} nums
 * @return {void} Do not return anything, modify nums in-place instead.
 */
 var moveZeroes = function (nums) {
    const len = nums.length
    if (len <= 1) return len
    let slow = 0, fast = 0
    while (fast < len) {
        if (nums[fast]) {
            slow !== fast && ([nums[slow], nums[fast]] = [nums[fast], nums[slow]])
            slow ++ 
        }
        fast ++ 
    }
};

/**
 * 要求原址操作，思路是拿到所有非0数组和0数组，清空原数组，最后根据非0数组和0数组按顺序生成新数组
 * @param {number[]} nums
 * @return {void} Do not return anything, modify nums in-place instead.
 */
var moveZeroes = function (nums) {
    if (!nums.some(v => v !== 0)) return nums
    const zeros = nums.filter(v => v === 0)
    const notZeros = nums.filter(v => v !== 0)
    nums.length = 0
    nums.push(...notZeros, ...zeros)
    return nums
};


/**
 * 要求原址操作，思路是拿到所有非0数组，覆盖原数组，最后根据原数组长度填0
 * 优点是节省了空间，没有额外开辟数组
 * @param {number[]} nums
 * @return {void} Do not return anything, modify nums in-place instead.
 */
var moveZeroes = function (nums) {
    if (!nums.some(v => v !== 0)) return nums
    const nonZeros = nums.filter(v => v !== 0)
    for (let index = 0; index < nums.length; index++) {
        nums[index] = nonZeros[index] || 0
    }
    return nums
};

/**
 * 要求原址操作，思路维持一个指针k, k永远指向当前数组第一个0元素，从而保证[0,k)中所有元素为非0元素
 * 优点是节省了空间，没有额外开辟数组
 * @param {number[]} nums
 * @return {void} Do not return anything, modify nums in-place instead.
 */
var moveZeroes = function (nums) {
    for (let index = 0, k = 0; index < nums.length; index++) {
        if (nums[index]) {
            index !== k && ([nums[index], nums[k]] = [nums[k], nums[index]])
            k++
        }
    }
    return nums
};