// 二叉树中节点之后等于某值的路径
func findPath(root *TreeNode, sum int) [][]int {
    return dfsFindPath(root, sum, 0, [][]int{}, &list.List{})
}

func dfsFindPath(root *TreeNode, sum int, countSum int, paths [][]int, path *list.List) [][]int {
    if root == nil {
        return paths
    }
    path.PushBack(root.Val)
    countSum += root.Val
    if root.Left != nil {
        paths = dfsFindPath(root.Left, sum, countSum, paths, path)
    }
    if root.Right != nil {
        paths = dfsFindPath(root.Right, sum, countSum, paths, path)
    }
    if root.Right == nil && root.Left == nil && countSum == sum {
        // 遍历链表获取路径
        newPath := make([]int, path.Len())
        node := path.Front()
        for i :=0; node != nil; i++ {
            newPath[i] = node.Value.(int)
            node = node.Next()
        }
        paths = append(paths, newPath)
    }
    path.Remove(path.Back())
    return paths
}