Create number-of-enclaves.py

Author: kamyu104

Python/number-of-enclaves.py

@@ -0,0 +1,25 @@
+# Time:  O(m * n)
+# Space: O(m * n)
+
+class Solution(object):
+    def numEnclaves(self, A):
+        """
+        :type A: List[List[int]]
+        :rtype: int
+        """
+        directions = [(0, -1), (0, 1), (-1, 0), (1, 0)]
+        def dfs(A, i, j):
+            if not (0 <= i < len(A) and 0 <= j < len(A[0]) and A[i][j]):
+                return
+            A[i][j] = 0
+            for d in directions:
+                dfs(A, i+d[0], j+d[1])
+        
+        for i in xrange(len(A)):
+            dfs(A, i, 0)
+            dfs(A, i, len(A[0])-1)
+        for j in xrange(1, len(A[0])-1):
+            dfs(A, 0, j)
+            dfs(A, len(A)-1, j)
+        return sum(sum(row) for row in A)
+