LeetCode #283 Move Zeroes 移动零

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.

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

示例 :
输入: [0,1,0,3,12]
输出: [1,3,12,0,0]

说明:

1. 必须在原数组上操做，不能拷贝额外的数组。
2. 尽可能减小操做次数。

思路:
设置两个指针, 数组前面的一部分交换为非 0值, 后面的直接设为 0
时间复杂度O(n), 空间复杂度O(1)

代码:
C++:

class Solution {
public:
    void moveZeroes(vector<int>& nums) {
        int i = 0, j = 0;
        for (; i < nums.size(); i++) {
            if (nums[i]) nums[j++] = nums[i];
        }
        for (; j < nums.size(); j++) nums[j] = 0;
    }
};

Java:

class Solution {
    public void moveZeroes(int[] nums) {
        int i = 0, j = 0;
        for (; i < nums.length; i++) {
            if (nums[i] != 0) nums[j++] = nums[i];
        }
        for (; j < nums.length; j++) nums[j] = 0;
    }
}

Python:

class Solution:
    def moveZeroes(self, nums: List[int]) -> None:
        """
        Do not return anything, modify nums in-place instead.
        """
        nums.sort(key = bool, reverse = True)

转载于:https://www.jianshu.com/p/bef01d731ea9