[leetcode]283.Move Zeroes

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.

Example:

Input: [0,1,0,3,12]
Output: [1,3,12,0,0]
Note:

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

解法一

思路

用两个指针，一个i用来遍历，一个j用来保存非0元素，保存一次就自增1。最后数组从j开始到结束都赋值为0即可。

代码

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

解法二

思路

和解法一思路其实一样，但是不进行赋值操作，而是进行交换操作。

代码

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