2454 - Next Greater Element IV\.

Hard

You are given a 0-indexed array of non-negative integers nums. For each integer in nums, you must find its respective second greater integer.

The second greater integer of nums[i] is nums[j] such that:

• j > i

• nums[j] > nums[i]

• There exists exactly one index k such that nums[k] > nums[i] and i < k < j.

If there is no such nums[j], the second greater integer is considered to be -1.

• For example, in the array [1, 2, 4, 3], the second greater integer of 1 is 4, 2 is 3, and that of 3 and 4 is -1.

Return an integer array answer, where answer[i] is the second greater integer of nums[i].

Example 1:

Input: nums = 2,4,0,9,6

Output: 9,6,6,-1,-1

Explanation:

0th index: 4 is the first integer greater than 2, and 9 is the second integer greater than 2, to the right of 2.

1st index: 9 is the first, and 6 is the second integer greater than 4, to the right of 4.

2nd index: 9 is the first, and 6 is the second integer greater than 0, to the right of 0.

3rd index: There is no integer greater than 9 to its right, so the second greater integer is considered to be -1.

4th index: There is no integer greater than 6 to its right, so the second greater integer is considered to be -1.

Thus, we return 9,6,6,-1,-1.

Example 2:

Input: nums = 3,3

Output: -1,-1

Explanation: We return -1,-1 since neither integer has any integer greater than it.

Constraints:

• <code>1 <= nums.length <= 10⁵</code>

• <code>0 <= numsi<= 10⁹</code>