leetcode - Move Zeroes

leetcode - Move Zeroes

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.

class Solution {
public:
    void moveZeroes(vector<int>& nums) {
        int pos = -1, i = 0;
        while(i<nums.size()){
            if(nums[i] != 0){
                nums[++pos] = nums[i];
            }
            i++;
        }
        while(pos+1<nums.size()){
            nums[++pos]=0;
        }
    }
};

思路：先把非零的数排到前面，并记录非零数最后的位置，然后把后面的其他数字都设置为0即可。

时间复杂度O(n), 空间复杂度 O(1)