4种创建二叉树的方法C/C++

#include <bits/stdc++.h>
using namespace std;

typedef char Element;
struct Node;
typedef struct Node *BTree;
struct Node{
   Element data;
   struct Node *lchild;
   struct Node *rchild;
};

BTree NewNode(Element x)
{
   BTree p=(BTree)malloc(sizeof(struct Node));
   p->data=x;
   p->lchild=NULL;
   p->rchild=NULL;
   return p;
}

//广义表创建二叉树    A(B(D,),C(E,F(,H)))
BTree Create_BTree(char s[])
{
   int k=0,top=-1;
   BTree path[100],p;
   for(int i=0;s[i]!='\0';i++){
       switch(s[i]){
           case '(':   path[++top]=p;   k=1;   break;
           case ',':   k=2;   break;
           case ')':   top--;   break;
       }
       if(isalpha(s[i])){
           p=NewNode(s[i]);
           if(k==1)
               path[top]->lchild=p;
           else if(k==2)
               path[top]->rchild=p;
       }
   }
   return path[0];
}

//递归创建二叉树   A(B(D,),C(E,F(,H)))
int Find(char s[],int left,int right)
{
   int k=0;
   for(int i=left;i<=right;i++){
       if(s[i]=='(')
           k++;
       if(s[i]==')')
           k--;
       if(s[i]==',' && k==1)
           return i;
   }
   return left;
}

BTree Create_BTree(char s[],int left,int right)
{
   int mid;
   if(left>right)
       return NULL;
   mid=Find(s,left,right);
   BTree root=NewNode(s[left]);
   root->lchild=Create_BTree(s,left+2,mid-1);
   root->rchild=Create_BTree(s,mid+1,right-1);
   return root;
}

//先序扩展创建二叉树   ABD...C..
BTree Create_BTree()
{
   BTree root;
   char c=getchar();
   if(c=='.')
       return NULL;
   root=NewNode(c);
   root->lchild=Create_BTree();
   root->rchild=Create_BTree();
   return root;
}

//根据先序和中序遍历确定二叉树先序：abdfgceh 中序：fdgbache

int Find(char in[],int start,int end,char x)
{
   for(int i=start;i<=end;i++)
       if(in[i]==x)
           return i;
   return -1;
}

BTree Create_BTree(char pre[],int s1,int e1,char in[],int s2,int e2)
{
   BTree root=NewNode(pre[s1]);
   int k=Find(in,s2,e2,pre[s1]);
   if(k!=s2)
       root->lchild=Create_BTree(pre,s1+1,s1+(k-s2),in,s2,k-1);
   if(k!=e2)
       root->rchild=Create_BTree(pre,s1+(k-s2)+1,e1,in,k+1,e2);
   return root;
}

4种创建二叉树的方法C/C++

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