[LeetCode] Wiggle Sort

Problem Description:

Given an unsorted array

nums

, reorder it in-place such that

nums[0] <= nums[1] >= nums[2] <= nums[3]...

.

For example, given

nums = [3, 5, 2, 1, 6, 4]

, one possible answer is

[1, 6, 2, 5, 3, 4]

.

The final sorted

nums

needs to satisfy two conditions:

If

i

is odd, then

nums[i] >= nums[i - 1]

;

If

i

is even, then

nums[i] <= nums[i - 1]

.

The code is just to fix the orderings of

nums

that do not satisfy 1 and 2.

class Solution {
public:
void wiggleSort(vector<int>& nums) {
int n = nums.size();
for (int i = 1; i < n; i++)
if (((i & 1) && nums[i] < nums[i - 1]) || (!(i & 1) && nums[i] > nums[i - 1]))
swap(nums[i], nums[i - 1]);
}
};