257. 二叉树的所有路径

/**
 * 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:
    void traver(TreeNode *t,vector&a,vector&ans){
        a.push_back(t->val);
        if(t->left==NULL&&t->right==NULL){
            string str;
            for(int i=0;ileft){
            traver(t->left,a,ans);
            a.pop_back();
        }
        if(t->right){
            traver(t->right,a,ans);
            a.pop_back();
        }
    }
    vector binaryTreePaths(TreeNode* root) {
        vectora;
        vectorans;
        if(root==NULL)return ans;
        traver(root,a,ans);
        return ans;
    }
};