二叉树--oj1

链接: link

class Solution {
public:vector<int> v;vector<int> preorderTraversal(TreeNode* root) {if(root==nullptr)return v;v.push_back(root->val);preorderTraversal(root->left);preorderTraversal(root->right);return v;}
};

链接: link

#include<iostream>
#include<string>
using std::cout;
using std::endl;
using std::string;
template<class T>
struct BTNode {BTNode(const T& data = T()): _left(nullptr),_right(nullptr),_data(data) {}BTNode<T>* _left;BTNode<T>* _right;T _data;
};template<typename T>
struct BTree {typedef BTNode<T> Node;typedef Node* pNode;static pNode CreatTree(string& s, int& ct) {if (s[ct] == '#') {ct++;return nullptr;}pNode root = new Node(s[ct++]);root->_left = CreatTree( s,  ct);root->_right = CreatTree( s,  ct);return root;}//前序创造static void PreOrder(pNode root) {if (root == NULL) {return;}PreOrder(root->_left);cout << root->_data <<" ";PreOrder(root->_right);}};int main() {string s;getline(std::cin, s);int ct = 0;auto a=BTree<char>::CreatTree(s, ct);BTree<char>::PreOrder(a);return 0;
}