题目

https://leetcode-cn.com/problems/path-sum-ii/

解题

  1. /**
  2.  * Definition for a binary tree node.
  3.  * function TreeNode(val, left, right) {
  4.  *     this.val = (val===undefined ? 0 : val)
  5.  *     this.left = (left===undefined ? null : left)
  6.  *     this.right = (right===undefined ? null : right)
  7.  * }
  8.  */
  9. /**
  10.  * @param {TreeNode} root
  11.  * @param {number} targetSum
  12.  * @return {number[][]}
  13.  */
  14. var pathSum = function(root, targetSum) {
  15.     if (root === null) {
  16.         return []
  17.     }
  18.     const result = []
  19.     const path = []
  21.     const dfs = (root, targetSum) => {
  22.         if (root === null) return
  23.         path.push(root.val)
  24.         targetSum -= root.val
  25.         if (!root.left && !root.right && targetSum === 0) { // 叶子节点
  26.             result.push([...path])
  27.         }
  30.         dfs(root.left, targetSum)
  31.         dfs(root.right, targetSum)
  33.         path.pop()
  34.     }
  35.     dfs(root, targetSum)
  37.     return result
  39. };