数据结构趣题——判断完全二叉树

   1: #include "stdio.h"

   2:  

   3: typedef struct BiTNode {

   4:     char data;   /*结点的数据域*/

   5:     struct BiTNode *lchild , *rchild;  /*指向左孩子和右孩子*/

   6: } BiTNode , *BiTree;

   7:  

   8: /*创建一棵二叉树*/

   9: void CreatBiTree(BiTree *T , int *level1 , int level2) {

  10:     char c;

  11:  

  12:     scanf("%c", &c);

  13:  

  14:     if(c == ' ') *T = NULL;

  15:     else {

  16:         *T = (BiTNode * )malloc(sizeof(BiTNode));           /*创建根结点*/

  17:         (*T)->data = c;                                    /*向根结点中输入数据*/

  18:  

  19:  

  20:         if(*level1 < level2) {

  21:             *level1 = level2;

  22:         }

  23:  

  24:  

  25:         CreatBiTree(&((*T)->lchild), &(*level1), level2 + 1); /*递归地创建左子树*/

  26:         CreatBiTree(&((*T)->rchild), &(*level1), level2 + 1); /*递归地创建右子树*/

  27:     }

  28: }

  29:  

  30:  

  31: int JusticCompleteBiTree(BiTree T, int level , int n, int flag) {

  32:     if(!T) {

  33:         return 1;

  34:     }

  35:  

  36:     if(level == n)

  37:     {

  38:  

  39:         if(T->lchild == NULL && T->rchild != NULL) return 0;

  40:  

  41:         if(flag == 0) { /*同层的前面的结点无空指针*/

  42:             if(T->rchild == NULL) flag = 1; /*出现空指针*/

  43:         }

  44:         else if(flag == 1) { /*同层的前面的结点有空指针*/

  45:             if(T->lchild != NULL || T->rchild != NULL)  return 0;

  46:         }

  47:     }

  48:  

  49:     if(level != n && level != n + 1)

  50:     {

  51:         if(T->lchild == NULL || T->rchild == NULL) return 0;

  52:     }

  53:  

  54:     if(!JusticCompleteBiTree(T->lchild, level + 1, n, flag)) return 0;

  55:  

  56:     if(!JusticCompleteBiTree(T->rchild, level + 1, n, flag)) return 0;

  57:  

  58:     return 1;

  59: }

  60:  

  61: int  main()

  62: {

  63:     BiTree T;

  64:     int level1 = 0;

  65:     printf("Please type some character to creat a binary tree\n");

  66:     CreatBiTree(&T, &level1, 0);

  67:  

  68:     if(JusticCompleteBiTree(T, 0, level1 - 1, 0))  printf("It is a complete binary tree\n");

  69:     else  printf("It is NOT a complete binary tree\n");

  70:  

  71:     return 0;

  72: }