leetcode257. 二叉树的所有路径

题目描述，链接https://leetcode-cn.com/problems/binary-tree-paths/

解题代码

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    vector<string> binaryTreePaths(TreeNode* root) {
        vector<vector<int>> paths;
        vector<string> spaths;
        if(root==NULL){
            return spaths;
        }
        vector<int> temp;
        temp.push_back(root->val);
        findPath(paths, temp, root);

        int size = paths.size();
        for(int i=0; i<size; i++){
            string str=to_string(paths[i][0]);
            int len = paths[i].size();
            for(int j=1; j<len; j++){
                str += "->";
                str += to_string(paths[i][j]);
            }
            spaths.push_back(str);
        }
        return spaths;
    }

    void findPath(vector<vector<int>>& paths, vector<int> temp, TreeNode* root){
        if(root->left==NULL && root->right==NULL){
            paths.push_back(temp);
            return;
        }
        if(root->left!=NULL){
            temp.push_back(root->left->val);
            findPath(paths, temp, root->left);
            temp.pop_back();
        }
        if(root->right!=NULL){
            temp.push_back(root->right->val);
            findPath(paths, temp, root->right);
            temp.pop_back();
        }

        return;
    }
};

运行结果