[LintCode] Wiggle Sort 扭动排序

Given an unsorted array nums, reorder it in-place such that

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

Please complete the problem in-place.

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

LeetCode上的原题，请参见我之前的博客Wiggle Sort。

解法一：

class Solution {
public:
    /**
     * @param nums a list of integer
     * @return void
     */  
    void wiggleSort(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        for (int i = 1; i < nums.size(); ++i) {
            if (i % 2 == 0) {
                swap(nums[i], nums[i - 1]);
            }
        }
    }
};

解法二：

class Solution {
public:
    /**
     * @param nums a list of integer
     * @return void
     */  
    void wiggleSort(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]);
            } 
        }
    }
};