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]
.Understand the problem:
A[0] <= A[1] >= A[2] <= A[3] >= A[4] <= A[5]
So we could actually observe that there is pattern that
A[even] <= A[odd],
A[odd] >= A[even].
Therefore we could go through the array and check this condition does not hold, just swap.
Code (Java):
public class Solution { public void wiggleSort(int[] nums) { if (nums == null || nums.length <= 1) { return; } for (int i = 0; i < nums.length - 1; i++) { if (i % 2 == 0) { if (nums[i] > nums[i + 1]) { swap(nums, i, i + 1); } } else { if (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; } }
code fails for this input : int[] nums = {3,3,1,5,4};
ReplyDeleteWhat is wrong with this input?
DeleteHere Question is modified as question includes the sign of equality where as original qustion does not !!!
ReplyDelete