Number Of Islands Solution

Author: naringst

number-of-islands/naringst.py

@@ -0,0 +1,44 @@
+from collections import deque 
+
+#  Runtime: 241ms, Memory: 18.94MB
+#  Time complexity: O(len(n*m))
+#  Space complexity: O(len(n*m))
+
+
+class Solution:
+    def bfs(self, a,b, grid, visited) :
+        n = len(grid)
+        m = len(grid[0])
+
+        dx = [0, 0, 1, -1]
+        dy = [1, -1 ,0 ,0]
+        q = deque()
+        q.append([a,b])
+        visited[a][b] = True
+
+        while q :
+            x,y = q.popleft()
+
+            for i in range(4) :
+                nx = x + dx[i]
+                ny = y + dy[i]
+
+                if (0 <= nx  < n and 0 <= ny < m and not visited[nx][ny] and grid[nx][ny] == '1'):
+                    visited[nx][ny] = True
+                    q.append([nx,ny])
+
+
+
+    def numIslands(self, grid: List[List[str]]) -> int:
+        n = len(grid)
+        m = len(grid[0])
+        visited = [[False] * m for _ in range(n)]
+        answer = 0
+        
+        for i in range(n) :
+            for j in range(m) :
+                if grid[i][j] == '1' and not visited[i][j] :
+                    self.bfs(i,j,grid,visited)
+                    answer += 1
+
+        return answer