Problem

Given a binary tree, return all root-to-leaf paths.

Note: A leaf is a node with no children.

Example

Input:

   1
 /   \
2     3
 \
  5

Output: ["1->2->5", "1->3"]

Explanation: All root-to-leaf paths are: 1->2->5, 1->3

Code

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
static int var = [](){
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();
class Solution {
private:
    vector<string> res;
public:
    vector<string> binaryTreePaths(TreeNode* root) {
        if(root==NULL)
            return res;
        translate("",root);
        return res;
    }
    void translate(string path,TreeNode* node){
        if(node->left==NULL && node->right==NULL){
            res.push_back(path+to_string(node->val));
        }
        else{
            if(node->left)
                translate(path+to_string(node->val)+"->",node->left);
            if(node->right)
                translate(path+to_string(node->val)+"->",node->right);
        }
    }
};

Result

257. Binary Tree Paths.png