200

Author: Jeldo

number-of-islands/jeldo.py

@@ -0,0 +1,19 @@
+class Solution:
+    # O(m*n), m = len(grid), n = len(grid[0])
+    def numgrids(self, grid: list[list[str]]) -> int:
+        def dfs(i, j):
+            if not (0 <= i < len(grid) and 0 <= j < len(grid[0])):
+                return
+            if grid[i][j] == "-1" or grid[i][j] == "0":
+                return
+            grid[i][j] = "-1"
+            for d in dirs:
+                dfs(i + d[0], j + d[1])
+        dirs = [(0, 1), (1, 0), (0, -1), (-1, 0)]
+        count = 0
+        for i in range(len(grid)):
+            for j in range(len(grid[0])):
+                if grid[i][j] == "1":
+                    count += 1
+                    dfs(i, j)
+        return count