63 Tree Sum

Table of Contents

Given a binary tree root, return the sum of all values in the tree.

Explanation

Recursively iterate through the tree. When we have a null node, we know we've gone too far, so return 0. Otherwise, the sum of the tree is represented by the current value + the sum of the left and right subtrees.

Solution

class Solution:
    def solve(self, root):
        if not root:
            return 0
        return root.val + self.solve(root.left) + self.solve(root.right)