Careercup - Microsoft面试题 - 5672369481842688

2014-05-12 06:27

题目链接

原题：

Find the max height of a binary tree.

题目：计算二叉树的最大高度。

解法：最大高度？高度不就是最深的叶子节点到根节点的路径长度吗？我就当是高度吧，递归解决。

代码：

// http://www.careercup.com/question?id=5672369481842688
#include <algorithm>
#include <iostream>
#include <sstream>
#include <string>
using namespace std;

struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int _val = 0): val(_val), left(nullptr), right(nullptr) {};
};

int height(TreeNode *root)
{
    return root ? 1 + max(height(root->left), height(root->right)) : 0;
}

void constructBinaryTree(TreeNode *&root)
{
    static int val;
    static string str;
    static stringstream sio;
    
    if (cin >> str && str != "#") {
        sio << str;
        sio >> val;
        root = new TreeNode(val);
        constructBinaryTree(root->left);
        constructBinaryTree(root->right);
    } else {
        root = nullptr;
    }
}

void deleteTree(TreeNode *&root)
{
    if (root == nullptr) {
        return;
    } else {
        deleteTree(root->left);
        deleteTree(root->right);
        delete root;
        root = nullptr;
    }
}

int main()
{
    TreeNode *root;
    
    while (true) {
        constructBinaryTree(root);
        if (root == nullptr) {
            break;
        }
        cout << height(root) << endl;
        deleteTree(root);
    }
    
    return 0;
}