题目

sum-root-to-leaf-numbers

算法

* 直接模拟

代码

class Solution {
public:
    vector<int> preorderTraversal(TreeNode *root) {
        vector<int> res;
        stack<TreeNode*> s;
        if (!root) return res;
        s.push(root);
        while (!s.empty()) {
            TreeNode *p = s.top();
            res.push_back(p->val);
            s.pop();
            if (p->right) s.push(p->right);
            if (p->left) s.push(p->left);
        }
        return res;
    }
};