leetcode刷题笔记(Golang)--129. Sum Root to Leaf Numbers

129. Sum Root to Leaf Numbers

Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.

An example is the root-to-leaf path 1->2->3 which represents the number 123.

Find the total sum of all root-to-leaf numbers.

Note: A leaf is a node with no children.

Example:

Input: [1,2,3]
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: [4,9,0,5,1]
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.

func sumNumbers(root *TreeNode) int {
	if root == nil {
		return 0
	}
	res := 0
	dfs(root, 0, &res)
	return res
}

func dfs(curr *TreeNode, path int, paths *int) {
	if curr.Left == nil && curr.Right == nil {
        fmt.Println()
		*paths += path*10+curr.Val
	}
	if curr.Left != nil {
		dfs(curr.Left, path*10+curr.Val, paths)
	}
	if curr.Right != nil {
		dfs(curr.Right, path*10+curr.Val, paths)
	}
}