数据结构与算法题目集（中文） 6-9 二叉树的遍历 (25分)

// #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 CreatBinTree(); /* 实现细节忽略 */
// void InorderTraversal( BinTree BT );
// void PreorderTraversal( BinTree BT );
// void PostorderTraversal( BinTree BT );
// void LevelorderTraversal( BinTree BT );

// int main()
// {
//     BinTree BT = CreatBinTree();
//     printf("Inorder:");    InorderTraversal(BT);    printf("\n");
//     printf("Preorder:");   PreorderTraversal(BT);   printf("\n");
//     printf("Postorder:");  PostorderTraversal(BT);  printf("\n");
//     printf("Levelorder:"); LevelorderTraversal(BT); printf("\n");
//     return 0;
// }

//space + char


//中序
void InorderTraversal( BinTree BT )   
{
    if (BT)
    {
        InorderTraversal( BT->Left);
        printf(" %c", BT->Data);
        InorderTraversal( BT->Right);
    }

}

//前序
void PreorderTraversal( BinTree BT )
{

    if (BT)
    {
        printf(" %c", BT->Data);
        PreorderTraversal(BT->Left);
        PreorderTraversal(BT->Right);
    }

}

   //后序
void PostorderTraversal( BinTree BT)
{
    if (BT)
    {
        PostorderTraversal(BT->Left);
        PostorderTraversal(BT->Right);
        printf(" %c", BT->Data);
    }
    

}
   //层遍历  用到队列知识
void LevelorderTraversal( BinTree BT )
{

    BinTree qu[2000];
    int head = 0, tail = 0;

    if (BT) qu[tail++] = BT;

    while (head < tail)
    {
        if(qu[head]->Left)  qu[tail++] = qu[head]->Left;    
        if(qu[head]->Right) qu[tail++] = qu[head]->Right;
        printf(" %c",qu[head++]->Data);  
    }
    
    
}