LeetCode 280. Wiggle Sort

I didn't come up the second method. I guess in limited time interview, it is quite hard to do so...

#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;

/*
  Given an unsorted array nums, reorder it in-place that
  nums[0] <= nums[1] >= nums[2] <= nums[3] >= nums[4] <= nums[5] >= nums[6]
  For example:
  Given nums = [3, 5, 2, 1, 6, 4], one possible answer is [1, 6, 2, 5, 3, 4]
*/
// Time complexity(NlgN)
void wiggleSort(vector<int>& nums) {
  sort(nums.begin(), nums.end());
  for(int i = 1; i < nums.size() - 1; i += 2) {
    swap(nums[i], nums[i + 1]);
  }
}

// what if we do not sort first.
void wiggleSortII(vector<int>& nums) {
  for(int i = 1; i < nums.size(); ++i) {
    if((i%2 == 1 && nums[i] < nums[i-1]) || (i%2 == 0 && nums[i] > nums[i-1])) {
      swap(nums[i], nums[i-1]);
    }
  }
}

int main(void) {
  vector<int> nums{3, 5, 2, 1, 6, 4};
  wiggleSortII(nums);
  for(int i = 0; i < nums.size(); ++i) {
    cout << nums[i] << " ";
  }
  cout << endl;
}