cpp-interview/DataStructure/HashTable.cpp

#include<stdio.h>
#include<stdlib.h>

#define SUCCESS 1
#define UNSUCCESS 0
#define OVERFLOW -1
#define OK 1
#define ERROR -1

typedef int Status;
typedef int KeyType;

typedef struct{
    KeyType key;
}RcdType;

typedef struct{
    RcdType *rcd;
    int size;
    int count;
    int *tag;
}HashTable;

int hashsize[] = { 11, 31, 61, 127, 251, 503 };
int index = 0;

Status InitHashTable(HashTable &H, int size){
    int i;
    H.rcd = (RcdType *)malloc(sizeof(RcdType)*size);
    H.tag = (int *)malloc(sizeof(int)*size);
    if (NULL == H.rcd || NULL == H.tag) return OVERFLOW;
    for (i = 0; i< size; i++)  H.tag[i] = 0;
    H.size = size;
    H.count = 0;
    return OK;
}

int Hash(KeyType key, int m){
    return (3 * key) % m;
}

void collision(int &p, int m){  //线性探测
    p = (p + 1) % m;
}

Status SearchHash(HashTable H, KeyType key, int &p, int &c) {
    p = Hash(key, H.size);
    int h = p;
    c = 0;
    while ((1 == H.tag[p] && H.rcd[p].key != key) || -1 == H.tag[p]){
        collision(p, H.size);  c++;
    }

    if (1 == H.tag[p] && key == H.rcd[p].key) return SUCCESS;
    else return UNSUCCESS;

}

void printHash(HashTable H) //打印哈希表
{
    int  i;
    printf("key : ");
    for (i = 0; i < H.size; i++)
        printf("%3d ", H.rcd[i].key);
    printf("\n");
    printf("tag : ");
    for (i = 0; i < H.size; i++)
        printf("%3d ", H.tag[i]);
    printf("\n\n");
}

Status InsertHash(HashTable &H, KeyType key);  //对函数的声明

//重构
Status recreateHash(HashTable &H){
    RcdType *orcd;
    int *otag, osize, i;
    orcd = H.rcd;
    otag = H.tag;                
    osize = H.size;     
                                
    InitHashTable(H, hashsize[index++]);
    //把所有元素，按照新哈希函数放到新表中
    for (i = 0; i < osize; i++){
        if (1 == otag[i]){     
            InsertHash(H, orcd[i].key);
        }
    }
}

Status InsertHash(HashTable &H, KeyType key){
    int p, c;
    if (UNSUCCESS == SearchHash(H, key, p, c)){ //没有相同key
        if (c*1.0 / H.size < 0.5){ //冲突次数未达到上线
            //插入代码
            H.rcd[p].key = key;
            H.tag[p] = 1;
            H.count++;        
            return SUCCESS;
         }
         else recreateHash(H); //重构哈希表 
    }
    return UNSUCCESS;
}
   
Status DeleteHash(HashTable &H, KeyType key){
    int p, c;
    if (SUCCESS == SearchHash(H, key, p, c)){
        //删除代码
        H.tag[p] = -1;
        H.count--;
          
        
        return SUCCESS;
    }
    else return UNSUCCESS;
}

void main()
{
    printf("-----哈希表-----\n");
    HashTable H;
    int i;
    int size = 11;
    KeyType array[8] = { 22, 41, 53, 46, 30, 13, 12, 67 };
    KeyType key;      
    RcdType e;
    
    //初始化哈希表
    printf("初始化哈希表\n");
    if (SUCCESS == InitHashTable(H, hashsize[index++])) printf("初始化成功\n");
    
    //插入哈希表
    printf("插入哈希表\n");
    for (i = 0; i <= 7; i++){
        key = array[i];
        InsertHash(H, key);
        printHash(H);
    }
    
    //删除哈希表
    printf("删除哈希表\n");
    int p, c;                            
    if (SUCCESS == DeleteHash(H, 12)) {
        printf("删除成功，此时哈希表为：\n");
        printHash(H);
    }
    
    //查询哈希表
    printf("查询哈希表\n");
    if (SUCCESS == SearchHash(H, 67, p, c)) printf("查询成功\n");
    
    //再次插入，测试哈希表的重构
    printf("再次插入，测试哈希表的重构：\n");
    KeyType array1[8] = { 27, 47, 57, 47, 37, 17, 93, 67 };        
    for (i = 0; i <= 7; i++){
        key = array1[i];
        InsertHash(H, key);
        printHash(H);
    }    
}