Sync LeetCode submission - Pacific Atlantic Water Flow (python3)

Author: kadhirash

problems/pacific_atlantic_water_flow/solution.py

@@ -0,0 +1,35 @@
+class Solution:
+    
+                    
+    def pacificAtlantic(self, matrix: List[List[int]]) -> List[List[int]]:
+        if not matrix:
+            return []
+
+        self.rows, self.cols = len(matrix), len(matrix[0])
+        p_visited = set()
+        a_visited = set()
+        self.directions = ((0, 1), (0, -1), (1, 0), (-1, 0))
+        
+        for row in range(self.rows):
+            self.traverse(row, 0, matrix,p_visited)
+            self.traverse(row, self.cols - 1, matrix,a_visited)
+
+        for col in range(self.cols):
+            self.traverse(0, col, matrix,p_visited)
+            self.traverse(self.rows - 1, col, matrix,a_visited)
+
+        return list(p_visited & a_visited)
+    
+    
+    def traverse(self,i, j, matrix,visited):
+        if (i, j) in visited:
+            return
+        visited.add((i, j))
+        # Traverse neighbors.
+        for direction in self.directions:
+            next_i, next_j = i + direction[0], j + direction[1]
+            if 0 <= next_i < self.rows and 0 <= next_j < self.cols:
+                if matrix[next_i][next_j] >= matrix[i][j]:
+                    self.traverse(next_i, next_j, matrix,visited)
+
+