Class Solution


  • public class Solution
    extends Object
    407 - Trapping Rain Water II.

    Hard

    Given an m x n integer matrix heightMap representing the height of each unit cell in a 2D elevation map, return the volume of water it can trap after raining.

    Example 1:

    Input: heightMap = [[1,4,3,1,3,2],[3,2,1,3,2,4],[2,3,3,2,3,1]]

    Output: 4

    Explanation:

     After the rain, water is trapped between the blocks.
     We have two small ponds 1 and 3 units trapped.
     The total volume of water trapped is 4. 
    

    Example 2:

    Input: heightMap = [[3,3,3,3,3],[3,2,2,2,3],[3,2,1,2,3],[3,2,2,2,3],[3,3,3,3,3]]

    Output: 10

    Constraints:

    • m == heightMap.length
    • n == heightMap[i].length
    • 1 <= m, n <= 200
    • 0 <= heightMap[i][j] <= 2 * 104
    • Constructor Detail

      • Solution

        public Solution()
    • Method Detail

      • trapRainWater

        public int trapRainWater​(int[][] heightMap)