Wiggle Sort

Question

Given an unsorted array nums, reorder it in-place such that nums[0] <= nums[1] >= nums[2] <= nums[3]….

Example:

Input: nums = [3,5,2,1,6,4]
Output: One possible answer is [3,5,1,6,2,4]

LeetCodeleetcode.com/problems/wiggle-sort

Solution

/*
@param: int[] nums
@return: 
Algorithm: 记录一个sign，表示先小于后大于，然后判断swap
*/
public void wiggleSort(int[] nums) {
    if (nums.length <= 1) {
        return;
    }
    
    boolean sign = true;
    for (int i = 0; i < nums.length-1; i++) {
        if (sign) {
            if (nums[i] > nums[i+1]) {
                swap(nums, i, i+1);
            }
        }else {
            if (nums[i] < nums[i+1]) {
                swap(nums, i, i+1);
            }
        }
        sign = !sign;
    }
}

public void swap(int[] nums, int i, int j) {
    int temp = nums[i];
    nums[i] = nums[j];
    nums[j] = temp;
}