二叉树中和为某一值的路径

输入一颗二叉树和一个整数，打印出二叉树中结点值的和为输入整数的所有路径。路径定义为从树的根结点开始往下一直到叶结点所经过的结点形成一条路径。

---

Python

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    # 返回二维列表，内部每个列表表示找到的路径
    def FindPath(self, root, expectNumber):
        # write code here
        if not root:
            return []
        if root and not root.left and not root.right and root.val == expectNumber:
            return [[root.val]]
        res = []
        left = self.FindPath(root.left, expectNumber-root.val)
        right = self.FindPath(root.right, expectNumber-root.val)
        for i in left+right:
            res.append([root.val]+i)
        return res

Java

import java.util.ArrayList;
/**
public class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;

    public TreeNode(int val) {
        this.val = val;

    }

}
*/
public class Solution {
    public ArrayList<ArrayList<Integer>> FindPath(TreeNode root,int target)
     {
            ArrayList<ArrayList<Integer>> resultLists = new ArrayList<>();
            if(root == null)
                return resultLists;
            ArrayList<Integer> pathLists = new ArrayList<>();
            int curSum = 0;
            isTargetPath(root, target, resultLists, pathLists, curSum);

            return resultLists;
     }

     public void isTargetPath(TreeNode root, int target, ArrayList<ArrayList<Integer>> resultLists, ArrayList<Integer> pathLists, int curSum)
     {
         if(root == null)
             return;
         curSum += root.val;
         //如果是叶节点
         if(root.left == null && root.right == null)
         {
             if(curSum == target)
             {
                 pathLists.add(root.val);
                 resultLists.add(new ArrayList<Integer>(pathLists));
                 //在返回父节点之前，在路径上删除当前结点
                 pathLists.remove(pathLists.size()-1);
             }
             return;
         }
         pathLists.add(root.val);
         isTargetPath(root.left, target, resultLists, pathLists, curSum);
         isTargetPath(root.right, target, resultLists, pathLists, curSum);
         pathLists.remove(pathLists.size()-1);
     }
}