首发于 语雀文档@blueju

    代码：

    1. /**
    2.  * Definition for a binary tree node.
    3.  * class TreeNode {
    4.  *     val: number
    5.  *     left: TreeNode | null
    6.  *     right: TreeNode | null
    7.  *     constructor(val?: number, left?: TreeNode | null, right?: TreeNode | null) {
    8.  *         this.val = (val===undefined ? 0 : val)
    9.  *         this.left = (left===undefined ? null : left)
    10.  *         this.right = (right===undefined ? null : right)
    11.  *     }
    12.  * }
    13.  */
    15. function sumRootToLeaf(root) {
    16.     if (root === null) return 0
    17.     const pathList = []
    18.     const dfs = (root, pathString) => {
    19.         if (root === null)
    20.             return
    21.         if (root.left === null && root.right === null) {
    22.             pathList.push(pathString + root.val)
    23.             return
    24.         }
    25.         dfs(root.left, pathString + root.val)
    26.         dfs(root.right, pathString + root.val)
    27.     }
    28.     dfs(root, '')
    29.     return pathList.reduce((prev, curr) => {
    30.         return prev + parseInt(curr, 2)
    31.     }, 0)
    32. };