965.-univalued-binary-tree.md

965. Univalued Binary Tree

• Easy
• A binary tree is uni-valued if every node in the tree has the same value.
• Given the root of a binary tree, return true if the given tree is uni-valued, or false otherwise.
• https://leetcode.com/problems/univalued-binary-tree/

Solution 1

Runtime: 28 msMemory Usage: 14.3 MB

class Solution:
    def isUnivalTree(self, root: Optional[TreeNode]) -> bool:
        if not root:
            return True
        if root.left:
            if root.left.val!=root.val:
                return False
        if root.right:
            if root.right.val!=root.val:
                return False
        return self.isUnivalTree(root.left) and self.isUnivalTree(root.right)

{% hint style="info" %} Simple recursive method. We only have to return the 'False situations' instead considering all the correct ones. {% endhint %}