7-47 打印选课学生名单 (25分)

 

 

解题思路：采用桶排序思想，将每个课程看成一个桶，再把每个课程对应学生放入桶，其中学生名单的采用二叉排序树结构存储

#include <stdio.h>
#include <malloc.h>
#include <string.h>

#define MaxSize 2503
#define MaxS 4
typedef char Element[MaxS+1];

typedef struct TNode *Tree;
struct TNode{
    Element Name;
    struct TNode *Left,*Right;
};

typedef struct HashTbl *HashTable;
struct HashTbl{
    int Num;
    Tree Next;
};
HashTable InitialHashTable(int Size);
void Insert(HashTable H,int CourseNo,Element Name);
Tree BuildBiSearchTree(Tree T,Element Name);
void Trav(Tree T);
void Out(HashTable H,int M);

int main()
{
    int N,M,i,j,n,CourseNo;
    Element Name;
    HashTable H;
    
    scanf("%d %d",&N,&M);
    H=InitialHashTable(M+1);
    
    for(i=0;i<N;i++)
    {
        scanf("%s%d",&Name,&n);
        
        for(j=0;j<n;j++)
        {
            scanf("%d",&CourseNo);
            Insert(H,CourseNo,Name);
        }
    }
    
    Out(H,M);
    return 0;
}


HashTable InitialHashTable(int Size)
{
    HashTable H=malloc(sizeof(struct HashTbl)*Size);
    while(Size)
    {
        H[--Size].Next=NULL;
        H[Size].Num=0;
    }
    return H;
}

void Insert(HashTable H,int CourseNo,Element Name)
{
    Tree T=H[CourseNo].Next;
    H[CourseNo].Num++;
    H[CourseNo].Next=BuildBiSearchTree(T,Name);
}

Tree BuildBiSearchTree(Tree T,Element Name)
{
    if(!T)
    {
        T=malloc(sizeof(struct TNode));
        strcpy(T->Name,Name);
        T->Left=NULL;
        T->Right=NULL;
    }
    else if(strcmp(Name,T->Name)<0)
    {
        T->Left=BuildBiSearchTree(T->Left,Name);
    }
    else
    {
        T->Right=BuildBiSearchTree(T->Right,Name);
    }
    return T;
}

void Trav(Tree T)
{
    if(T)
    {
        Trav(T->Left);
        printf("%s\n",T->Name);
        Trav(T->Right);
    }
}
void Out(HashTable H,int M)
{
    int i;
    for(i=1;i<=M;i++)
    {
        printf("%d %d\n",i,H[i].Num);
        Tree T=H[i].Next;
        Trav(T);
    }
}