hashtable.go

package main

import "fmt"

const ArraySize = 7

// has table hold the array
type HashTable struct {
	array [ArraySize]*Bucket
}

// will hold link list
type Bucket struct {
	head *BucketNode
}

// bucket node is the link lsit node that hold the key
type BucketNode struct {
	key  string
	next *BucketNode
}

// insert will take the key and add it to the bucket
func (h *HashTable) Insert(key string) {
	index := hash(key)
	h.array[index].insert(key)
}

// // search will take the key and return true if it exists
func (h *HashTable) Search(key string) bool {
	index := hash(key)
	return h.array[index].search(key)
}

// // delete will delete the bucket
func (h *HashTable) Delete(key string) {
	index := hash(key)
	h.array[index].delete(key)
}

// hash
func hash(key string) int {
	sum := 0

	for _, v := range key {
		sum += int(v)
	}

	return sum % ArraySize

}

// insert will insert key into the bucket

func (b *Bucket) insert(k string) {

	if b.search(k) {
		fmt.Println(k, "already exist")
		return
	}

	newNode := &BucketNode{key: k}
	// make new node and make next node to be the previous
	newNode.next = b.head
	// point the previous node head to the new node head
	b.head = newNode
}

func (b *Bucket) search(key string) bool {
	currentNode := b.head
	for currentNode != nil {
		if currentNode.key == key {
			return true
		}

		currentNode = currentNode.next
	}

	return false

}

func (b *Bucket) delete(key string) {

	if b.head.key == key {
		b.head = b.head.next
		return
	}

	previosNode := b.head

	for previosNode.next != nil {
		if previosNode.next.key == key {
			previosNode.next = previosNode.next.next
		}

		previosNode = previosNode.next
	}
}

// init bucket node
func Init() *HashTable {
	result := &HashTable{}

	for i := range result.array {

		result.array[i] = &Bucket{}
	}

	return result
}

func main() {
	hashtable := Init()

	list := []string{
		"ERIC",
		"sagar",
		"Sagar",
		"SAGAR",
		"Junmin Lee",
		"Keya",
	}

	for _, v := range list {
		hashtable.Insert(v)
	}

	fmt.Println(hashtable)
	fmt.Println(hashtable.Search("SAGAR"))
	hashtable.Delete("Keya")
	fmt.Println(hashtable)
	fmt.Println(hashtable.Search("Keya"))
}