[ppxyn1] WEEK 15 solutions

subtree-of-another-tree/ppxyn1.py

@@ -0,0 +1,36 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, val=0, left=None, right=None):
+#         self.val = val
+#         self.left = left
+#         self.right = right
+
+
+# idea : BFS
+# Time Complexity : O(size of root * size of subRoot)
+from collections import deque
+
+class Solution:
+    def isSubtree(self, root: Optional[TreeNode], subRoot: Optional[TreeNode]) -> bool:
+        queue = deque([root])
+
+        while queue:
+            node = queue.popleft()
+
+            if node:
+                if self.isSame(node, subRoot):
+                    return True
+                queue.append(node.left)
+                queue.append(node.right)
+
+        return False
+
+    def isSame(self, r, s):
+        if not r and not s:
+            return True
+        if not r or not s:
+            return False
+        if r.val != s.val:
+            return False
+        return self.isSame(r.left, s.left) and self.isSame(r.right, s.right)
+