[LeetCode283]Move Zeros将一个数组中为0的元素移至数组末尾

题目：

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:

1. You must do this in-place without making a copy of the array.
2. Minimize the total number of operations.

思路：可以该数组从后向前遍历，遇到0就把0放至末尾；或者从前遍历遇到非0元素则依次放在数组前，最后将后边元素全部置为0

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace LeetCode
{
    class MoveZerosSolution
    {
        public void MoveZeroes(int[] nums)
        {
            //O(n2)
            for (int i = nums.Length - 1; i >= 0; i--)
            {
                if (nums[i] == 0)
                {
                    for (int j = i; j < nums.Length - 1; j++)
                    {
                        nums[j] = nums[j + 1];
                    }
                    nums[nums.Length - 1] = 0;
                }

            }
            /*O(1)解法
        
            int index = 0;
            for(int i = 0;i < nums.Length;i++)
                if(nums[i] != 0)
                {
                    nums[index] = nums[i];
                    index++;
                }
            for(int j = index;j < nums.Length;j++)
                nums[j] = 0;
        
            */
        }
    }
}