g0401_0500.s0417_pacific_atlantic_water_flow

Class Solution

java.lang.Object

g0401_0500.s0417_pacific_atlantic_water_flow.Solution

public class Solution
extends Object

417 - Pacific Atlantic Water Flow.

Medium

There is an m x n rectangular island that borders both the Pacific Ocean and Atlantic Ocean. The Pacific Ocean touches the island’s left and top edges, and the Atlantic Ocean touches the island’s right and bottom edges.

The island is partitioned into a grid of square cells. You are given an m x n integer matrix heights where heights[r][c] represents the height above sea level of the cell at coordinate (r, c).

The island receives a lot of rain, and the rain water can flow to neighboring cells directly north, south, east, and west if the neighboring cell’s height is less than or equal to the current cell’s height. Water can flow from any cell adjacent to an ocean into the ocean.

Return a 2D list of grid coordinates result where result[i] = [ri, ci] denotes that rain water can flow from cell (ri, ci) to both the Pacific and Atlantic oceans.

Example 1:

Input: heights = [[1,2,2,3,5],[3,2,3,4,4],[2,4,5,3,1],[6,7,1,4,5],[5,1,1,2,4]]

Output: 0,4],[1,3],[1,4],[2,2],[3,0],[3,1],[4,0

Example 2:

Input: heights = [[2,1],[1,2]]

Output: 0,0],[0,1],[1,0],[1,1

Constraints:

• m == heights.length
• n == heights[r].length
• 1 <= m, n <= 200
• 0 <= heights[r][c] <= 105

Constructor Summary

Constructors

Constructor and Description
Solution()

Method Summary

Modifier and Type	Method and Description
List<List<Integer>>	pacificAtlantic(int[][] matrix)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Solution

public Solution()

Method Detail

pacificAtlantic

public List<List<Integer>> pacificAtlantic(int[][] matrix)