https://leetcode-cn.com/problems/er-cha-shu-zhong-he-wei-mou-yi-zhi-de-lu-jing-lcof/
var path = [Int]()
var result = [[Int]]()
func pathSum(_ root: TreeNode?, _ sum: Int) -> [[Int]] {
pathSumAction(root, sum)
return result
}
func pathSumAction(_ root: TreeNode?, _ sum: Int) {
if root == nil {
return
}
var Sum = sum
//记录经过的路径
path.append(root!.val)
Sum = Sum - root!.val
//判断路径是否符合
if Sum == 0 && root?.left == nil && root?.right == nil {
result.append(path)
}
//前序遍历
pathSumAction(root?.left, Sum)
pathSumAction(root?.right, Sum)
//返回上一节点路径
path.removeLast()
}
