Wiggle Sort II

Given an unsorted array nums, reorder it such that nums[0] < nums[1] > nums[2] < nums[3]....

Example:
(1) Given nums = [1, 5, 1, 1, 6, 4], one possible answer is [1, 4, 1, 5, 1, 6].
(2) Given nums = [1, 3, 2, 2, 3, 1], one possible answer is [2, 3, 1, 3, 1, 2].

Note:
You may assume all input has valid answer.

Follow Up:
Can you do it in O(n) time and/or in-place with O(1) extra space?

class Solution {
public:
    void wiggleSort(vector<int>& nums) {
        int n = nums.size();
        if (n < 1)
        {
            return;
        }
        sort(nums.begin(), nums.end());

        vector<int> temp(n, 0);
        int j = n-1;
        for (int i = 1; i < n; i += 2, j--)
        {
            temp[i] = nums[j];
        }
        for (int i = 0; i < n; i += 2, j--)
        {
            temp[i] = nums[j];
        }

        nums = temp;
    }
};