void binaryTreePathsHelper(string s,vector<string>& result,TreeNode* node)
{
if(node == 0)
{
return;
}
if(node->left == 0 && node->right == 0)
{
s += to_string(node->val);
result.push_back(s);
return;
}
s += to_string(node->val) + "->";
binaryTreePathsHelper(s,result,node->left);
binaryTreePathsHelper(s,result,node->right);
}
void binaryTreePathsHelper(TreeNode* root, vector<int> solution, vector<string>& result ) {
if (!root) return;
solution.push_back(root->val);
//meet the leaf node, shape a path into the result
if (root->left==NULL && root->right==NULL){
if(solution.size()>0){
stringstream ss;
for(int i=0; i<solution.size(); i++){
ss << solution[i] << (i<solution.size()-1 ? "->":"");
}
result.push_back(ss.str());
}
return;
}
binaryTreePathsHelper(root->left, solution, result);
binaryTreePathsHelper(root->right, solution, result);
}
vector<string> binaryTreePaths(TreeNode* root)
{
vector<string> ret;
binaryTreePathsHelper("",ret,root);
return ret;
}
vector<string> binaryTreePaths(TreeNode* root) {
vector<string> result;
vector<int> solution;
binaryTreePathsHelper(root, solution, result);
return result;
}