subtree-of-another-tree py3

0572_subtree-of-another-tree/README.md

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+Given the roots of two binary trees `root` and `subRoot`, return `true` if there is a subtree of `root` with the same structure and node values of `subRoot` and `false` otherwise.
+
+A subtree of a binary tree `tree` is a tree that consists of a node in `tree` and all of this node's descendants. The tree `tree` could also be considered as a subtree of itself.
+
+**Example 1:**
+
+![](https://assets.leetcode.com/uploads/2021/04/28/subtree1-tree.jpg)
+
+    Input: root = [3,4,5,1,2], subRoot = [4,1,2]
+    Output: true
+    
+
+**Example 2:**
+
+![](https://assets.leetcode.com/uploads/2021/04/28/subtree2-tree.jpg)
+
+    Input: root = [3,4,5,1,2,null,null,null,null,0], subRoot = [4,1,2]
+    Output: false
+    
+
+**Constraints:**
+
+*   The number of nodes in the `root` tree is in the range `[1, 2000]`.
+*   The number of nodes in the `subRoot` tree is in the range `[1, 1000]`.
+*   `-104 <= root.val <= 104`
+*   `-104 <= subRoot.val <= 104`
+
+https://leetcode.com/problems/subtree-of-another-tree

0572_subtree-of-another-tree/python3/solution.py

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+# 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
+class Solution:
+    def isSubtree(self, root: Optional[TreeNode], subRoot: Optional[TreeNode]) -> bool:
+        if subRoot is None:
+            return True
+        elif root is None:
+            return False
+        
+        if self.isSameTree(root, subRoot):
+            return True
+        
+        return self.isSubtree(root.left, subRoot) or self.isSubtree(root.right, subRoot)
+        
+        
+    def isSameTree(self, a, b):
+        if a is None and b is None:
+            return True
+        elif a is None or b is None or a.val != b.val:
+            return False
+        
+        return self.isSameTree(a.left, b.left) and self.isSameTree(a.right, b.right)