#include<iostream>
#include<string>
#include<cctype>
#include<fstream>
#include<algorithm>
using namespace std;
const int MaxSize = 97;
typedef struct Element {
int info;//info的用處是用來標記元素是否被刪除過
int num;
}Element;
typedef struct HashTable {
int tablesize;//散列表的大小
Element *restore;
}H,*Hash;
Hash create(int size) { //創建一個大小爲size的散列表
Hash hr = new struct HashTable;
if (hr == NULL) cout << "空間溢出";
hr->tablesize = size;
hr->restore = (Element*)malloc(size * sizeof(Element));
for (int i = 0; i < hr->tablesize; i++) {
hr->restore[i].info = 0;//info=1時表示表被佔用,info=0時表示空,info=-1時表示元素被刪除
}
return hr;
}
int hash_search(int number, Hash h)//構造散列函數
{
return number % (h->tablesize);
}
int find_position(int key, Hash h)//平方探測
{
int cnum = 0;//記錄衝突次數
int judge = 0;
for (int i = 0; i < h->tablesize; i++) {
if (h->restore[i].info == 0||h->restore[i].info==-1) {
judge = 1; break;
}
}
int pos1, pos2;
int position = hash_search(key, h);
int newpos = position;
while (h->restore[newpos].info == 1) {
cnum++;
if (cnum % 2 == 0) {
newpos = position + (cnum + 1) / 2 * (cnum + 1) / 2;
while (newpos >= h->tablesize) newpos -= h->tablesize;
}
else {
newpos = position - (cnum) / 2 * (cnum) / 2;
while (newpos < 0) newpos += h->tablesize;
}
}
if (judge==0) cout << "散列表已滿無法找到空位" << endl;
return newpos;
}
void insert(int key, Hash h) {
int pos = find_position(key, h);
h->restore[pos].num = key;
h->restore[pos].info = 1;
}
void delete_number(int key, Hash h) {
for (int i = 0; i < h->tablesize; i++) {
if (h->restore[i].num == key) {
h->restore[i].info = -1;
break;
}
}
}
int find_a_key(int key, Hash h) {//查找一個元素是否在散列表中
int position = hash_search(key, h);
int newpos = position;
int cnum = 0;
while (h->restore[newpos].num != key) {
cnum++;
if( (h->restore[newpos].info == 0)||(h->restore[newpos].info==-1&&h->restore[newpos].num==key) ){
cout << "該元素不在表中"; break;
}
if (cnum % 2 == 0) {
newpos = position + (cnum + 1) / 2 * (cnum + 1) / 2;
while (newpos >= h->tablesize) newpos -= h->tablesize;
}
else {
newpos = position - (cnum) / 2 * (cnum) / 2;
while (newpos < 0) newpos += h->tablesize;
}
}
return newpos;
}
int main()
{
Hash h = create(97);
int n;
cout << "請輸入數字數目 ";
cin >> n;
for (int i = 0; i < n; i++) {
int a; cin >> a;
insert(a, h);
}
delete_number(32, h);
cout << find_a_key(204, h);
}
基於開放地址法的哈希表(散列表)
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