Brooke

一、題目

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]

 

Constraints:

• 1 <= nums.length <= 104
• -231 <= nums[i] <= 231 - 1

 

Follow up: Could you minimize the total number of operations done?

 

二、程式作法

public class Solution
{
    public void MoveZeroes(int[] nums)
    {
        int counter = 0;
        for (int i = 0; i < nums.Length; i++)
            if (nums[i] != 0)
                nums[i - counter] = nums[i];
            else
                counter++;

        for (int i = nums.Length - counter; i < nums.Length; i++)
            nums[i] = 0;
    }
}

 

三、思路筆記

題目要的結果是將所有的零移到陣列的尾巴，並且不能使用額外空間。

那我們在每次移動元素時，判斷是否為零，是的話，計數到零的次數，並不移動，

否的話，才往前移動元素，

當移完之後，後面剩下的空間就直接補零就好。