Number of Islands Solution

Author: Jinbeom

number-of-islands/kayden.py

@@ -0,0 +1,36 @@
+# 시간복잡도: O(M*N)
+# 공간복잡도: O(M*N)
+
+from collections import deque
+
+
+class Solution:
+    def numIslands(self, grid: List[List[str]]) -> int:
+        dx = [0, 0, -1, 1]
+        dy = [-1, 1, 0, 0]
+        m = len(grid)
+        n = len(grid[0])
+        q = deque()
+
+        def bfs(a, b):
+            q.append((a, b))
+            while q:
+                x, y = q.popleft()
+
+                for i in range(4):
+                    nx = x + dx[i]
+                    ny = y + dy[i]
+                    if not (0 <= nx < m and 0 <= ny < n): continue
+
+                    if grid[nx][ny] == '1':
+                        grid[nx][ny] = '0'
+                        q.append((nx, ny))
+
+        count = 0
+        for i in range(m):
+            for j in range(n):
+                if grid[i][j] == '1':
+                    count += 1
+                    bfs(i, j)
+
+        return count