adding algo

Author: ivanpenaloza

src/my_project/interviews/top_amazon_questions_round_1/rotting_oranges.py

@@ -0,0 +1,38 @@
+from typing import List 
+from collections import deque
+
+class Solution:
+    def orangesRotting(self, grid: List[List[int]]) -> int:
+        freshy = 0
+        time = 0
+        m = len(grid)
+        n = len(grid[0])
+
+        q = deque()
+
+        # Queue all rotten oranges and count fresh ones
+        for r in range(m):
+            for c in range(n):
+                if grid[r][c] == 1:
+                    freshy += 1
+                if grid[r][c] == 2:
+                    q.append((r, c))
+
+        # Run multi-source BFS
+        while q:
+            rotten_oranges = 0
+            for _ in range(len(q)):
+                r, c = q.popleft()
+                for dr, dc in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
+                    new_r, new_c = r + dr, c + dc
+                    if 0 <= new_r < m and 0 <= new_c < n and grid[new_r][new_c] == 1:
+
+                        q.append((new_r, new_c))
+                        grid[new_r][new_c] = 2
+                        freshy -= 1
+                        rotten_oranges += 1
+
+            if rotten_oranges > 0:
+                time += 1
+
+        return time if freshy == 0 else -1