Solution: Next Greater Element IV
Understand how to use two stacks to determine the second greater element for each number in an array. This lesson covers the approach to track elements waiting for first and second greater values, enabling a single pass solution with linear time complexity and efficient space usage.
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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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