按广义表输入形式建立二叉树

 

#include
#include



#define MaxSize 100

typedef char ElemType;

typedef struct node
{
 ElemType data;
 struct node *lchild;
 struct node *rchild;
}BTNode;


BTNode *CreateBTNode(char *str)
{
 //str是二叉树的广义表表示的字符串
 //st是栈空间，b是新建二叉链表的根指针
 BTNode *St[MaxSize],*P = NULL,*b;
 int top = -1,k,j = 0;
 char ch;
 ch = str[j];
 //初始化的二叉链为空
 b = NULL;

 for (j = 0; str[j] != '\0';j ++)
 {
  ch = str[j];
  switch (ch)
  {
  //作为左结点
  case '(':
   top ++;
   St[top] = P;
   k =1;
   break;
  case ')':
   top --;
   break;
  //作为右结点
  case ',':
   k = 2;
   break;
  default:
   P = (BTNode *)malloc(sizeof(BTNode));
   P->data = ch;
   P->lchild = P->rchild = NULL;
   if (b == NULL)
   {
    // p指向二叉树的根结点
    b = P;
   }
   else
   {
    switch(k)
    {
    case 1:
     St[top]->lchild = P;
     break;
    case 2:
     St[top]->rchild = P;
     break;
    }
   }
  }
 }
 return b;
}


void DispBTNode(BTNode *b)
{
 //打印用的队列
 BTNode *qu[MaxSize];
 BTNode *p;
 int front,rear,n;
 //初始化层号
 n = 0;
 front = rear =0;
 qu[rear ++] = NULL;
 p = b;
 if (p != NULL)
 {
  qu[rear ++] = p;
 }
 do
 {
  //出队队首指针
  p = qu[front ++];
  //出队指针为空
  if (p == NULL)
  {
   //队列中进入空指针作为分层标志
   qu[rear ++] = NULL;
   //层号加一
   n ++;
   printf("\n");
  }
  else
  {
   printf("(%d,,)",n,p->data);
   if (p->lchild != NULL)
   {
    qu[rear ++] = p->lchild;
   }
   if (p->rchild != NULL)
   {
    qu[rear ++] = p->rchild;
   }
  }
 } while (front != rear -1);
}


void main()
{
 BTNode *b;
 b = CreateBTNode("A(B(D(G,H(J,K)),E),C(,F(,(I(M))))");
 printf("\n");
 printf("用分层的形式输出二叉树:\n");
 DispBTNode(b);
 printf("\n");
}

 

转载于:https://blog.51cto.com/591819849/1100782