Hash Table - Hashing with Chaining
Incredibly, the Array.prototype.fill will fill each item with the same Object.
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| class Node {
constructor(value) {
this.next = null
this.value = value
}
}
class Hash_Table {
constructor(size = 16) {
this.size = size
this.data = new Array(this.size)
for (let i = 0; i < this.size; i++) {
this.data[i] = { next: null }
}
}
_hash(string) {
let hash = 5381
string
.toString()
.split("")
.map((i) => (hash = (hash << 5) + hash + i.charCodeAt(0)))
return hash
}
insert(key, value) {
let pointer = this.data[this._hash(key) % this.size]
if (!pointer.next) {
pointer.next = new Node(value)
} else {
while (pointer.next) {
pointer = pointer.next
if (pointer.value === value) return
}
pointer.next = new Node(value)
}
}
get(key) {
let pointer = this.data[this._hash(key) % this.size],
result = []
if (!pointer.next) return new Error("Doesn't exist.")
else {
do {
pointer = pointer.next
result.push(pointer.value)
} while (pointer.next)
return result
}
}
delete(key) {
this.data[this._hash(key) % this.size] = { next: null }
}
}
let hash = new Hash_Table()
hash.insert("test", 3)
hash.insert("test", 5)
hash.insert("test", 5)
hash.insert("test", 6)
hash.insert(12, 44)
hash.insert(11, 3)
hash.insert(10, 3)
console.log(hash.get("test"))
hash.delete(12)
console.log(hash.get(12))
|
result:
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2
| Array(3) [3, 5, 6]
Error: Doesn't exist.
|