[LeetCode] Wiggle Sort

Wiggle Sort

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].

贪心，数学归纳法很容易证明出来。

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