Leetcode 144 Solution

This article provides solution to leetcode question 144 (binary-tree-preorder-traversal)

https://leetcode.com/problems/binary-tree-preorder-traversal

Solution

/** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public: vector<int> preorderTraversal(TreeNode* root) { stack<TreeNode*> s;
if (root) s.push(root);
vector<int> res; while (s.empty() == false) { auto p = s.top(); s.pop();
res.push_back(p->val);
if (p->right) s.push(p->right); if (p->left) s.push(p->left); }
return res; } };