LeetCode 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].

解题思路：

The final sorted nums needs to satisfy two conditions:

1. If i is odd, then nums[i] >= nums[i - 1];
2. 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.

Java code:

public class Solution {
    public void wiggleSort(int[] nums) {
        for(int i = 1; i < nums.length; i++){
            if( (i % 2 == 1 && nums[i] < nums[i-1]) || (i % 2 == 0 && nums[i] > nums[i-1])){
                swap(nums, i, i-1);
            }
        }
    }
    
    private void swap(int[] nums, int i, int j){
        int temp = nums[i];
        nums[i] = nums[j];
        nums[j] = temp;
    }
}

Reference:

1. http://www.cnblogs.com/jcliBlogger/p/4797531.html