leetcode113

class Solution:
    def __init__(self):
        self.lists = []
        
    def preOrder(self,root,path,sums,target):
        if root != None:
            path.append(root.val)
            sums += root.val
            if root.left != None:
                self.preOrder(root.left,path,sums,target)
            if root.right != None:
                self.preOrder(root.right,path,sums,target)
            
            if root.left == None and root.right == None:
                if sums == target:
                    self.lists.append(path[:])
            path.pop(-1)
            sums -= target
    
    def pathSum(self, root: TreeNode, sum: int) -> 'List[List[int]]':
        self.preOrder(root,[],0,sum)
        return self.lists

本题是leetcode112的升级版，需要检查多条路径，并保存。