हैश टेबल एक डेटा संरचना है जिसका उपयोग कुंजी-मूल्य जोड़े को संग्रहीत करने के लिए किया जाता है। हैश फ़ंक्शन का उपयोग हैश टेबल द्वारा एक सरणी में एक इंडेक्स की गणना करने के लिए किया जाता है जिसमें एक तत्व डाला या खोजा जाएगा।
डबल हैशिंग ओपन एड्रेस्ड हैश टेबल्स में टकराव समाधान की एक तकनीक है। डबल हैशिंग टकराव होने पर कुंजी के लिए दूसरी हैश फ़ंक्शन का उपयोग करने के विचार का उपयोग करती है।
यह डबल हैशिंग के साथ हैश टेबल्स चेनिंग को लागू करने के लिए एक C++ प्रोग्राम है।
एल्गोरिथम
कुंजी खोजने के लिए:
Begin Declare Function SearchKey(int k, HashTable *ht) int hashVal= HashFunc1(k, ht->s) int stepSize= HashFunc2(k, ht->s) while (ht->t[hashVal].info != Emp and ht->t[hashVal].e != k) hashVal = hashVal + stepSize hashVal = hashVal % ht->s return hashVal End
सम्मिलन के लिए:
Begin. Declare Function Insert(int k, HashTable *ht) int pos = SearchKey(k, ht) if (ht->t[pos].info != Legi ) ht->t[pos].info = Legi ht->t[pos].e = k End
प्रदर्शन के लिए:
Begin Declare function display(HashTable *ht) for (int i = 0; i < ht->s; i++) int v= ht->t[i].e; if (!v) Print "Position: " Print the position of the pointer Print " Element: Null" else Print "Position: " Print the position of the pointer Print " Element: " Print the element End.
रीहैश फ़ंक्शन के लिए:
Begin Declare function Rehash(HashTable *ht) int s = ht->s HashTableEntry *t= ht->t ht = initiateTable(2*s) for (int i = 0; i < s; i++) if (t[i].info == Legi) Insert(t[i].e, ht) free(t) return ht End.
उदाहरण कोड
#include <iostream> #include <cstdlib> #define T_S 5 using namespace std; enum EntryType {Legi, Emp}; struct HashTableEntry { int e; enum EntryType info; }; struct HashTable { int s; HashTableEntry *t; }; int HashFunc1(int k, int s) { return k % s; } int HashFunc2(int k, int s) { return (k * s - 1) % s; } HashTable *initiateTable(int s) { HashTable *ht; if (s < T_S) { cout<<"Table Size is Too Small"<<endl; return NULL; } ht= new HashTable; if (ht == NULL) { cout<<"Out of Space"<<endl; return NULL; } ht->s = s; ht->t = new HashTableEntry[ht->s]; if (ht->t== NULL) { cout<<"Table Size is Too Small"<<endl; return NULL; } for (int i = 0; i < ht->s; i++) { ht->t[i].info = Emp; ht->t[i].e=NULL; } return ht; } int SearchKey(int k, HashTable *ht) { int hashVal= HashFunc1(k, ht->s); int stepSize= HashFunc2(k, ht->s); while (ht->t[hashVal].info != Emp && ht->t[hashVal].e != k) { hashVal = hashVal + stepSize; hashVal = hashVal % ht->s; } return hashVal; } void Insert(int k, HashTable *ht) { int pos = SearchKey(k, ht); if (ht->t[pos].info != Legi ) { ht->t[pos].info = Legi; ht->t[pos].e = k; } } void display(HashTable *ht) { for (int i = 0; i < ht->s; i++) { int v= ht->t[i].e; if (!v) cout<<"Position: "<<i + 1<<" Element: Null"<<endl; else cout<<"Position: "<<i + 1<<" Element: "<<v<<endl; } } HashTable *Rehash(HashTable *ht) { int s = ht->s; HashTableEntry *t= ht->t; ht = initiateTable(2*s); for (int i = 0; i < s; i++) { if (t[i].info == Legi) Insert(t[i].e, ht); } free(t); return ht; } int main() { int v, s, pos, i = 1; int c; HashTable *ht; while(1) { cout<<"1.Initialize size of the table"<<endl; cout<<"2.Insert element into the table"<<endl; cout<<"3.Display Hash Table"<<endl; cout<<"4.Rehash Hash Table"<<endl; cout<<"5.Exit"<<endl; cout<<"Enter your choice: "; cin>>c; switch(c) { case 1: cout<<"Enter size of the Hash Table: "; cin>>s; ht = initiateTable(s); break; case 2: if (i > ht->s) { cout<<"Table is Full, Rehash the table"<<endl; continue; } cout<<"Enter element to be inserted: "; cin>>v; Insert(v, ht); i++; break; case 3: display(ht); break; case 4: ht= Rehash(ht); break; case 5: exit(1); default: cout<<"\nEnter correct option\n"; } } return 0; }
आउटपुट
1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 1 Enter size of the Hash Table: 4 Table Size is Too Small Enter your choice: 1 Enter size of the Hash Table: 10 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 1 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 3 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 4 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 5 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 6 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 7 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 8 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 9 Enter correct option 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 9 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 10 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 11 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Table is Full, Rehash the table 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 12 Enter correct option 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Table is Full, Rehash the table 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Table is Full, Rehash the table 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 3 Position: 1 Element: 10 Position: 2 Element: 1 Position: 3 Element: 11 Position: 4 Element: 3 Position: 5 Element: 4 Position: 6 Element: 5 Position: 7 Element: 6 Position: 8 Element: 7 Position: 9 Element: 8 Position: 10 Element: 9 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 4 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 3 Position: 1 Element: Null Position: 2 Element: 1 Position: 3 Element: Null Position: 4 Element: 3 Position: 5 Element: 4 Position: 6 Element: 5 Position: 7 Element: 6 Position: 8 Element: 7 Position: 9 Element: 8 Position: 10 Element: 9 Position: 11 Element: 10 Position: 12 Element: 11 Position: 13 Element: Null Position: 14 Element: Null Position: 15 Element: Null Position: 16 Element: Null Position: 17 Element: Null Position: 18 Element: Null Position: 19 Element: Null Position: 20 Element: Null 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 2 Enter element to be inserted: 20 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 3 Position: 1 Element: 20 Position: 2 Element: 1 Position: 3 Element: Null Position: 4 Element: 3 Position: 5 Element: 4 Position: 6 Element: 5 Position: 7 Element: 6 Position: 8 Element: 7 Position: 9 Element: 8 Position: 10 Element: 9 Position: 11 Element: 10 Position: 12 Element: 11 Position: 13 Element: Null Position: 14 Element: Null Position: 15 Element: Null Position: 16 Element: Null Position: 17 Element: Null Position: 18 Element: Null Position: 19 Element: Null Position: 20 Element: Null 1.Initialize size of the table 2.Insert element into the table 3.Display Hash Table 4.Rehash Hash Table 5.Exit Enter your choice: 5
