problem42

README

< Previous 　　　　　　　　　　　　　　　　 Next >

42. 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
• 0 <= n <= 3 * 104
• 0 <= height[i] <= 105

Related Topics

[Stack] [Array] [Two Pointers] [Dynamic Programming]

Similar Questions

1. Container With Most Water (Medium)
2. Product of Array Except Self (Medium)
3. Trapping Rain Water II (Hard)
4. Pour Water (Medium)