leetcode129-sum-root-to-leaf-numbers_dfs1.cpp

#include<algorithm>
#include<vector>
#include<iostream>
usingnamespacestd;

/**
 * Definition for a binary tree node.
*/
structTreeNode
{
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) {}
};

classSolution {
private:
int sum = 0;
 string pathStr;

public:
intsumNumbers(TreeNode *root) {
dfs(root);
return sum;
 }

private:
voiddfs(TreeNode *root) {
if (root == nullptr) return;

 pathStr.push_back(root->val + '0');
if (root->left == nullptr && root->right == nullptr)
 sum += stoi(pathStr);
else
 {
if (root->left != nullptr)
dfs(root->left);
if (root->right != nullptr)
dfs(root->right);
 }
 pathStr.pop_back();
 }
};

// Test
intmain()
{
 Solution sol;
 TreeNode* root = newTreeNode(1);
 root->left = newTreeNode(2);
 root->left->left = nullptr;
 root->left->right = nullptr;
 root->right = newTreeNode(3);
 root->right->left = nullptr;
 root->right->right = nullptr;

auto res = sol.sumNumbers(root);
 cout << res << endl; 

return0;
}