Trap Rain Water Between Bars | Dataford Interview Questions

In a Meta-style coding interview, you are given an array height where each element represents the height of a vertical bar in an elevation map. Return the total amount of rain water that can be trapped after raining.

Formal Specification

Input: height, a list of non-negative integers
Output: An integer representing the total units of trapped water

Water above index i is determined by the shorter of the tallest bar to its left and right, minus height[i], if that value is positive.

Constraints

1 <= len(height) <= 2 * 10^4
0 <= height[i] <= 10^5
Return the total trapped water as an integer

Function Signature

def trap_rain_water(height):

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Problem