7-9 还原二叉树（25 分）

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。

输入格式:

输入首先给出正整数N（≤50），为树中结点总数。下面两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（区别大小写）的字符串。

输出格式:

输出为一个整数，即该二叉树的高度。

输入样例:

9
ABDFGHIEC
FDHGIBEAC

输出样例:

5


代码：

#include <stdio.h>
#include <stdlib.h>

char x[50],z[50];
typedef struct TreeNode *Tree;
struct TreeNode
{
    char data;
    Tree right,left;
};
Tree CreatNode()
{
    Tree p = (Tree)malloc(sizeof(struct TreeNode));
    p -> left = p -> right = NULL;
    return p;
}
Tree RestoreTree(int x1,int x2,int z1,int z2)
{
    Tree head = CreatNode();
    head -> data = x[x1];
    for(int i = z1;i <= z2;i ++)
    {
        if(z[i] == x[x1])
        {
            if(i != z1)head -> left = RestoreTree(x1 + 1,x1 + i - z1,z1,i - 1);
            if(i != z2)head -> right = RestoreTree(x1 + i - z1 + 1,x2,i + 1,z2);
            break;
        }
    }
    return head;
}
int max(int a,int b)
{
    if(a>b)return a;
    return b;
}
int Theight(Tree tree)
{
    if(tree == NULL)return 0;
    return max(Theight(tree -> left),Theight(tree -> right))+1;
}
int main()
{
    int n;
    scanf("%d",&n);
    scanf("%s%s",x,z);
    Tree head = RestoreTree(0,n-1,0,n-1);
    printf("%d",Theight(head));
}