Solution: Next Greater Element IV
Understand how to solve the Next Greater Element IV problem using two stacks to track elements waiting for their first and second greater values. Learn to implement an efficient O(n) time solution that updates results in a single iteration, mastering stack usage for complex array problems.
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Statement
You are given a 0-indexed array of non-negative integers nums. For each element nums[i], determine its second greater element and return an array res where res[i] contains the second greater element of nums[i].
The second greater element of
nums[i]is defined as the valuenums[j]such that:
j > i
nums[j] > nums[i]There exists exactly one index
kwherei < k < jandnums[k] > nums[i]If no such index
jexists, then the second greater element fornums[i]is-1.
Constraints:
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