数据结构实验之二叉树四：（先序中序）还原二叉树

数据结构实验之二叉树四：（先序中序）还原二叉树
Time Limit: 1000MS Memory Limit: 65536KB
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Problem Description

给定一棵二叉树的先序遍历序列和中序遍历序列，要求计算该二叉树的高度。
Input

输入数据有多组，每组数据第一行输入1个正整数N(1 <= N <= 50)为树中结点总数，随后2行先后给出先序和中序遍历序列，均是长度为N的不包含重复英文字母(区分大小写)的字符串。

Output

输出一个整数，即该二叉树的高度。
Example Input

9
ABDFGHIEC
FDHGIBEAC
Example Output

5
Hint

Author

xam

#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;


const int MAX = 55;

typedef struct node
{
    char data;
    struct node *cl, *cr;
} tree, *ptree;



ptree get_pretree(int n, char pre[], char mid[])
{
    if (n == 0)
        return NULL;
    char *p;
    for (p = mid; p != '\0'; p++)
    {
        if (*p == pre[0])
            break;
    }
    int len = p - mid;
    ptree root = new tree;
    root->data = pre[0];
    root->cl = get_pretree(len, pre + 1, mid);
    root->cr = get_pretree(n - len - 1, pre + len + 1, p + 1);
    return root;
}

int get_deep(ptree root)
{
    if (root == NULL)
        return 0;
    int dp = 0;
    int dl = get_deep(root->cl);
    int dr = get_deep(root->cr);
    dp = dl > dr ? dl + 1 : dr + 1;
    return dp;
}


int main()
{
    char pre[MAX], mid[MAX];
    int n;
    while (cin >> n)
    {
        cin >> pre >> mid;
        ptree root = NULL;
        root = get_pretree(n, pre, mid);
        int ct = get_deep(root);
        cout << ct << endl;
    }
    return 0;
}