Medium
Quiz
#129 Sum Root to Leaf Numbers
APPROACH
The root of a binary tree is given where every node holds a digit from 0 to 9.
Each root-to-leaf path encodes a number (for example, the path 1 -> 2 -> 3 represents 123).
Return the total sum of all numbers formed by root-to-leaf paths. The answer is guaranteed to fit in a 32-bit integer.
A leaf is a node with no children.
Example 1:
Input: root = [1,2,3]
Output: 25
Explanation:
The root-to-leaf path 1->2 represents the number 12.
The root-to-leaf path 1->3 represents the number 13.
Therefore, sum = 12 + 13 = 25.
Example 2:
Input: root = [4,9,0,5,1]
Output: 1026
Explanation:
The root-to-leaf path 4->9->5 represents the number 495.
The root-to-leaf path 4->9->1 represents the number 491.
The root-to-leaf path 4->0 represents the number 40.
Therefore, sum = 495 + 491 + 40 = 1026.
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What is the optimal approach for this problem?