图 哈希存储

哈希存储

1.开放地址法

哈希表数据结构

const int NULLKEY = -1;
const int DELKEY = -1;
typedef int KeyType;
struct HashTable
{
 KeyType key;
 int count;
};

哈希表插入与创建

void InsertHT(HashTable ha[], int &n, int m, int p, KeyType k)
{
 int i, adr;
 adr = k % p;
 if (ha[adr].key == NULLKEY || ha[adr].key == DELKEY)
 {
  ha[adr].key = k;
  ha[adr].count = 1;
 }
 else
 {
  i = 1;
  do
  {
   adr = (adr + 1) % m;
   i++;
  } while (ha[adr].key == NULLKEY || ha[adr].key == DELKEY);
  ha[adr].key = k;
  ha[adr].count = i;
 }
 n++;
}


void CreateHT(HashTable ha[], int &n, int m, int p, KeyType keys[], int n1)
{
 for (int i = 0; i < m; i++)
 {
  ha[i].key = NULLKEY;
  ha[i].count = 0;
 }
 n = 0;
 for (int i = 0; i < n1; i++)
  InsertHT(ha, n, m, p, keys[i]);
}

哈希表查找与删除

void SearchHT(HashTable ha[], int m, int p, KeyType k)
{
 int i = 1, adr;
 adr = k % p;
 while (ha[adr].key != NULLKEY && ha[adr].key != k)
 {
  i++;
  adr = (adr + 1) % m;
 }
 if (ha[adr].key == k)  cout << "关键字:" << k << " 查找成功  此次比较次数: " << i << endl;
 else  cout << "关键字:" << k << " 查找失败  此次比较次数: " << i << endl;
}


bool DeleteHT(HashTable ha[], int &n, int m, int p, KeyType k)
{
 int adr;
 adr = k % p;
 while (ha[adr].key != NULLKEY && ha[adr].key != k)
  adr = (adr + 1) % m;
 if (ha[adr].key == k)
 {
  ha[adr].key = DELKEY;
  return true;
 }
 else
  return false;
}

2.拉链法

哈希表数据结构

typedef int KeyType;
struct NodeType
{
 KeyType key;
 NodeType *next;
};
struct HashTable
{
 NodeType *firstp;
};

哈希表插入与创建

void InsertHT(HashTable ha[], int &n, int p, KeyType k)
{
 int adr;
 adr = k % p;
 NodeType *q;
 q = new NodeType;
 q->key = k;
 q->next = NULL;
 if (ha[adr].firstp == NULL)
  ha[adr].firstp = q;
 else
 {
  q->next = ha[adr].firstp;
  ha[adr].firstp = q;
 }
 n++;
}
void CreateHT(HashTable ha[], int &n, int m, int p, KeyType keys[], int n1)
{
 for (int i = 0; i < m; i++)
  ha[i].firstp = NULL;
 n = 0;
 for (int i = 0; i < n1; i++)
  InsertHT(ha, n, p, keys[i]);
}

哈希表查找与删除

void Search(HashTable ha[], int p, KeyType k)
{
 int adr, i = 0;
 adr = k % p;
 NodeType *q;
 q = ha[adr].firstp;
 while (q != NULL)
 {
  i++;
  if (q->key == k)
   break;
  q = q->next;
 }
 if (q != NULL)  cout << "关键字:" << k << " 查找成功  此次比较次数: " << i << endl;
 else  cout << "关键字:" << k << " 查找失败  此次比较次数: " << i << endl;
}

bool DeleteHT(HashTable ha[], int &n, int m, int p, KeyType k)
{
 int adr;
 adr = k % p;
 NodeType *q, *preq;
 q = ha[adr].firstp;
 if (q == NULL)
  return false;
 if (q->key == k)
 {
  ha[adr].firstp = q->next;
  delete q;
  n--;
  return true;
 }
 preq = q; q = q->next;
 while (q != NULL)
 {
  if (q->key == k)
   break;
  q = q->next;
 }
 if (q != NULL)
 {
  preq->next = q->next;
  delete q;
  n--;
  return true;
 }
 else
  return false;
}