[Swift]LeetCode283. 移动零 | Move Zeroes

★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★
➤微信公众号：山青咏芝（shanqingyongzhi）
➤博客园地址：山青咏芝（https://www.cnblogs.com/strengthen/）
➤GitHub地址：https://github.com/strengthen/LeetCode
➤原文地址：https://www.cnblogs.com/strengthen/p/9756870.html 
➤如果链接不是山青咏芝的博客园地址，则可能是爬取作者的文章。
➤原文已修改更新！强烈建议点击原文地址阅读！支持作者！支持原创！
★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★

热烈欢迎，请直接点击！！！

进入博主App Store主页，下载使用各个作品！！！

注：博主将坚持每月上线一个新app！！！

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:

[0,1,0,3,12]
[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.

---

给定一个数组 nums，编写一个函数将所有 0 移动到数组的末尾，同时保持非零元素的相对顺序。

示例:

[0,1,0,3,12]
[1,3,12,0,0]

说明:

1. 必须在原数组上操作，不能拷贝额外的数组。
2. 尽量减少操作次数。

---

 

16ms

class Solution {
    func moveZeroes(_ nums: inout [Int]) {
        //0要后移，反意是非0元素前移。
        if nums == nil || nums.count == 0
        {
            return
        }
        //记录非0元素开始位置
        var j:Int = 0
        for i in 0..<nums.count
        {
            if nums[i] != 0
            {             
                nums[j] = nums[i]
                j += 1
            }
        }
        while(j < nums.count)
        {
            nums[j] = 0
            j += 1
        }
    }
}

---

16ms

class Solution {
    func moveZeroes(_ nums: inout [Int]) {
        var firstPointer = 0 
        var secondPointer = 0
         
        while secondPointer < nums.count {
            if nums[firstPointer] == 0 {
                if nums[secondPointer] != 0 {
                    swap(&nums, firstPointer, secondPointer)
                } else {
                    secondPointer += 1
                }
            } else {
                secondPointer += 1
                firstPointer += 1
            }
        }
    }
    
    func swap(_ nums: inout [Int], _ firstIndex: Int, _ secondIndex: Int) {
        var temp = nums[firstIndex]
        nums[firstIndex] = nums[secondIndex]
        nums[secondIndex] = temp
    }
}

---

16ms

class Solution {
    func moveZeroes(_ nums: inout [Int]) {
        var index1 = 0
        var index2 = nums.count
        while index1 <= index2 - 1 {
            if nums[index1] == 0 {
                for _ in 0..<(index2-index1) {
                    index2 -= 1
                    if nums[index2] != 0 {
                        nums.remove(at: index1)
                        nums.append(0)
                        break;
                    }
                }
            }else {
                index1 += 1
            }
        }
    }
}

---

20ms

class Solution {
    func moveZeroes(_ nums: inout [Int]) {
        var removedCount = 0
        for (idx, val) in nums.enumerated() {
            if val == 0 {
                nums.remove(at: idx-removedCount)
                removedCount += 1
                nums.append(0)
            }
        }
    }
}