找BUG 深度优先搜索 切片BUG 可变参数

https://leetcode-cn.com/problems/er-cha-shu-zhong-he-wei-mou-yi-zhi-de-lu-jing-lcof/

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func pathSum(root *TreeNode, target int) [][]int {
	if root == nil {
		return nil
	}
	var l [][]int
	var dfs func(t *TreeNode, v int, ll ...int)
	dfs = func(t *TreeNode, v int, ll ...int) {
		if t == nil {
			return
		}
		v += t.Val
		if v > target {
			return
		}
		if v == target {
			ll = append(ll, t.Val)
			l = append(l, ll)
			return
		}
		ll = append(ll, t.Val)
		dfs(t.Left, v, ll...)
		dfs(t.Right, v, ll...)
		return
	}
	dfs(root, 0)
	return l
}

　　

1、题意理解

2、取值范围

3、语法

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func pathSum(root *TreeNode, target int) [][]int {
	if root == nil {
		return nil
	}
	var l [][]int
	var dfs func(t *TreeNode, v int, ll ...int)
	dfs = func(t *TreeNode, v int, ll ...int) {
		if t == nil {
			return
		}
		v += t.Val
		f := func() []int {
			l := append([]int{}, ll...)
			l = append(l, t.Val)
			return l
		}
		if v == target {
			if t.Left == nil && t.Right == nil {
				l = append(l, f())
				return
			}
		}
		dfs(t.Left, v, f()...)
		dfs(t.Right, v, f()...)
		return
	}
	dfs(root, 0)
	return l
}