Trapping Rain Water — C# Coding Problem
Difficulty: hard | Category: array
Problem Description
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. Hint: For each position, the water trapped equals `min(maxLeft, maxRight) - height[i]`. Use two pointers for an O(n) solution.
Examples
Example 1
Input: height = [0, 1, 0, 2, 1, 0, 1, 3, 2, 1, 2, 1]
Output: 6
Example 2
Input: height = [4, 2, 0, 3, 2, 5]
Output: 9