LintCode-376.二叉树的路径和

二叉树的路径和

给定一个二叉树，找出所有路径中各节点相加总和等于给定 目标值 的路径。
一个有效的路径，指的是从根节点到叶节点的路径。

样例

给定一个二叉树，和 目标值 = 5:

返回：
[
    [1, 2, 2],
    [1, 4]
]

标签

二叉树 二叉树遍历

code

/**
 * Definition of TreeNode:
 * class TreeNode {
 * public:
 *     int val;
 *     TreeNode *left, *right;
 *     TreeNode(int val) {
 *         this->val = val;
 *         this->left = this->right = NULL;
 *     }
 * }
 */
class Solution {
public:
    /**
     * @param root the root of binary tree
     * @param target an integer
     * @return all valid paths
     */
    vector<vector<int> > binaryTreePathSum(TreeNode *root, int target) {
        // Write your code here
        vector<vector<int> > result;
        vector<int> order;
        TreeNode *p=root;
        int path=0;

        if(root == NULL) {
            return result;
        }
        else {
            path = 0;
            findPath(root, target, order, path, result);
            return result;
        }
    }

    void findPath(TreeNode *root, int target, vector<int> &order, int &path, vector<vector<int> > &result) {
        path += root->val;
        order.push_back(root->val);

        if(path == target && (root->left==NULL&&root->right==NULL)) {
            result.push_back(order);
        }

        if(root->left != NULL)
            findPath(root->left, target, order, path, result);
        if(root->right != NULL)
            findPath(root->right, target, order, path, result);

        path -= root->val;
        order.pop_back();
    }
};