Coding

A coding task on screen, then a follow-up and a deeper question.

Description

Trapping Rain Water

Hard

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.

Example 1:

Input: height = [0,1,0,2,1,0,1,3,2,1,2,1]

Output: 6

Explanation: The above elevation map (black section) is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain water (blue section) are being trapped.

Example 2:

Input: height = [4,2,0,3,2,5]

Output: 9

Constraints:

n == height.length
1 <= n <= 2 * 10⁴
0 <= height[i] <= 10⁵

CodeJavaScript

1/**
2 * @param {number[]} height
3 * @return {number}
4 */
5var trap = function(height) {
6    
7};

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