查找五：散列表查找

Posted 2020-08-14 jx_yangbo

 1 //散列表
 2 #include<iostream>
 3 using namespace std;
 4 #define NULLKEY -32768
 5 #define HASHSIZE 12 //定义散列表长度为12
 6 
 7 struct HashTable
 8 {
 9     int *elem;  //数据元素存储基址
10     int count;  //当前数组元素个数
11 };
12 
13 int m = 0; //散列表长度
14 
15 //初始化散列表
16 bool InitHashTable(HashTable *H)
17 {
18     m = HASHSIZE;
19     H->count = m;
20     H->elem = new int[m];
21     for(int i=0;i<m;i++)
22         H->elem[i] = NULLKEY;
23     return true;
24 }
25 
26 //散列函数
27 int Hash(int key)
28 {
29     return key % m;
30 }
31 
32 //插入关键字进散列表
33 void InsertHash(HashTable *H, int key)
34 {
35     int addr = Hash(key);
36     while(H->elem[addr] != NULLKEY)
37     {
38         addr = (addr+1)%m;
39     }
40     H->elem[addr] = key;
41 }
42 
43 //散列表查找关键字
44 bool SearchHash(HashTable H, int key, int *addr)
45 {
46     *addr = Hash(key);
47     while(H.elem[*addr] != key)
48     {
49         *addr = (*addr+1)%m;
50         if(H.elem[*addr]==NULLKEY || *addr == Hash(key))
51             return false;
52     }
53     return true;
54 }
55 
56 int main()
57 {
58     int arr[HASHSIZE]={12,67,56,16,25,37,22,29,15,47,48,34};
59     int i,p,key,result;
60     HashTable H;
61 
62     key=39;
63 
64     InitHashTable(&H);
65     for(i=0;i<m;i++)
66          InsertHash(&H,arr[i]);
67     
68     result=SearchHash(H,key,&p);
69     if (result)
70         cout<<"查找 "<< key <<" 的地址为："<<p<<endl;
71     else
72         cout<<"查找 "<< key <<" 失败。"<<endl;
73 
74     for(i=0;i<m;i++)
75     {
76         key=arr[i];
77         SearchHash(H,key,&p);
78         cout<<"查找 "<< key <<" 的地址为："<<p<<endl;
79     }
80 
81     return 0;
82 }