C++ Solution

[SimingYan]

class Solution {
public:
vector<string> a;
vector<string> binaryTreePaths(TreeNode* root) {
if(root==NULL){
return a;
}
if(!root->left && !root->right){
a.push_back(to_string(root->val));
return a;
}
if(root->left)
get_path(root->left, to_string(root->val));
if(root->right)
get_path(root->right, to_string(root->val));
return a;
}
void get_path(TreeNode* root, string prefix){
if(!root->left && !root->right)
a.push_back(prefix + "->" + to_string(root->val));
if(root->left){
get_path(root->left, prefix + "->" + to_string(root->val));
}
if(root->right){
get_path(root->right, prefix + "->" + to_string(root->val));
}
}
};