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:

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?

DeleteDoesn't work for 1,1,3,3,2,2

ReplyDeleteGives 1 3 1 3 2 2

A correct solution could have been 1 2 1 3 2 3

Here Question is modified as question includes the sign of equality where as original qustion does not !!!

ReplyDelete