数据结构趣题——判断完全二叉树

#include "stdio.h"

typedef struct BiTNode {
    char data;   /*结点的数据域*/
    struct BiTNode *lchild , *rchild;  /*指向左孩子和右孩子*/
} BiTNode , *BiTree;

/*创建一棵二叉树*/
void CreatBiTree(BiTree *T , int *level1 , int level2) {
    char c;

    scanf("%c", &c);

    if(c == ' ') *T = NULL;
    else {
        *T = (BiTNode * )malloc(sizeof(BiTNode));           /*创建根结点*/
        (*T)->data = c;                                    /*向根结点中输入数据*/


        if(*level1 < level2) {
            *level1 = level2;
        }


        CreatBiTree(&((*T)->lchild), &(*level1), level2 + 1); /*递归地创建左子树*/
        CreatBiTree(&((*T)->rchild), &(*level1), level2 + 1); /*递归地创建右子树*/
    }
}


int JusticCompleteBiTree(BiTree T, int level , int n, int flag) {
    if(!T) {
        return 1;
    }

    if(level == n)
    {

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

        if(flag == 0) { /*同层的前面的结点无空指针*/
            if(T->rchild == NULL) flag = 1; /*出现空指针*/
        }
        else if(flag == 1) { /*同层的前面的结点有空指针*/
            if(T->lchild != NULL || T->rchild != NULL)  return 0;
        }
    }

    if(level != n && level != n + 1)
    {
        if(T->lchild == NULL || T->rchild == NULL) return 0;
    }

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

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

    return 1;
}

int  main()
{
    BiTree T;
    int level1 = 0;
    printf("Please type some character to creat a binary tree\n");
    CreatBiTree(&T, &level1, 0);

    if(JusticCompleteBiTree(T, 0, level1 - 1, 0))  printf("It is a complete binary tree\n");
    else  printf("It is NOT a complete binary tree\n");

    return 0;
}