_503. Next Greater Element II.md

503. Next Greater Element II

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First completed : July 05, 2024

Last updated : July 05, 2024

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Related Topics : Array, Stack, Monotonic Stack

Acceptance Rate : 65.19 %

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Since Python supports array index calls overflowing to the end, we can start from the max value present, add it to a running stack of the next max value in descending order, and iterate len(nums) times to find the value for each index.

In other languages, this wrapping would have to be added in manually.

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Solutions

• m503.py

Python

m503.py

class Solution:
    def nextGreaterElements(self, nums: List[int]) -> List[int]:
        maxIndx = max(list(range(len(nums))), key=lambda x: nums[x])
        stk = [nums[maxIndx]]
        output = [0] * len(nums)
        
        for i in range(maxIndx - 1, maxIndx - 1 - len(nums), -1) :
            while stk and stk[-1] <= nums[i] :
                stk.pop()
            if stk :
                output[i] = stk[-1]
            else :
                output[i] = -1
            stk.append(nums[i])

        return output