PTA练习题：还原二叉树

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

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

typedef char ElementType;
typedef struct TNode *Position;
typedef Position BinTree;
struct TNode{
    ElementType Data;
    BinTree Left;
    BinTree Right;
};

BinTree SetBinTree(char per[],char od[]);
int GetIndex(char s[],char c);
int GetHeight( BinTree BT );

int i = 0;

int main()
{
	int n;
	scanf("%d",&n);
	getchar();
	char per[51];
	char od[51];
	gets(per);
	gets(od);
	BinTree BT = SetBinTree(per,od);
	printf("%d\n",GetHeight(BT));
	return 0;
}

BinTree SetBinTree(char per[],char od[])
{
	int x = GetIndex(od,per[i]);
	if( x == -1)
	{
		i--;
		return NULL;
	}
	BinTree T = (BinTree)malloc(sizeof(struct TNode));
	T->Data = per[i];
	char od1[51];
	char od2[51];
	int count1 = 0;
	int count2 = 0;
	for(int j=0;j<x;j++)
	{
		od1[count1++] = od[j];
	}
	for(int j=x+1;od[j]!='\0';j++)
	{
		od2[count2++] = od[j];
	}
	i++;
	T->Left = SetBinTree(per,od1);
	i++;
	T->Right = SetBinTree(per,od2);
	return T;
}
int GetIndex(char s[],char c)
{
	for(int i=0;s[i]!='\0';i++)
	{
		if(s[i] == c)
		{
			return i;
		}
	}
	return -1;
}
int GetHeight( BinTree BT )
{
	if(BT == NULL)
	{
		return 0;
	}
	return GetHeight(BT->Left)+1>GetHeight(BT->Right)+1? GetHeight(BT->Left)+1:GetHeight(BT->Right)+1;
}