Udemy: Master Coing Interview - Hash Tables - #78
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using System;
using System.Collections.Generic;
class HashTable {
public struct KeyValue {
public string key;
public int value;
}
public LinkedList<KeyValue>[] data;
public int size;
static void Main() {
Console.WriteLine("Hello World!");
HashTable myHashTable = new HashTable(2);
myHashTable.Set("grapes", 10000);
myHashTable.Set("grapes1", 10001);
myHashTable.Set("grapes2", 10002);
myHashTable.Set("grapes3", 10003);
Console.WriteLine("Hash('grapes') = " + myHashTable.Get("grapes"));
Console.WriteLine("Hash('grapes1') = " + myHashTable.Get("grapes1"));
Console.WriteLine("Hash('grapes2') = " + myHashTable.Get("grapes2"));
Console.WriteLine("Hash('grapes3') = " + myHashTable.Get("grapes3"));
Console.WriteLine("Keys = " + ToString(myHashTable.Keys()));
}
public static string ToString(string[] strings) {
string s = "{";
int count = 0;
foreach (string str in strings) {
if (count > 0) {
s += ", ";
}
s += str;
count++;
}
s += "}";
return s;
}
public HashTable(int size) {
this.data = new LinkedList<KeyValue>[size];
this.size = size;
}
public void Set(string key, int value) {
int address = this.Hash(key);
if (this.data[address] == null) {
this.data[address] = new LinkedList<KeyValue>();
}
KeyValue kv = new KeyValue();
kv.key = key;
kv.value = value;
this.data[address].AddLast(kv);
}
public int Get(string key) {
int address = this.Hash(key);
if (this.data[address] != null) {
foreach (KeyValue kv in this.data[address]) {
if (kv.key == key) {
return kv.value;
}
}
}
return 0;
}
public string[] Keys() {
string[] temp = new string[100];
int keyCount = 0;
for (int i = 0; i < this.data.Length; i++) {
if (this.data[i] != null) {
foreach (KeyValue kv in this.data[i]) {
temp[keyCount] = kv.key;
keyCount++;
}
}
}
string[] keys = new string[keyCount];
for (int i = 0; i < keyCount; i++) {
keys[i] = temp[i];
}
return keys;
}
private int Hash(string key) {
int position = key.GetHashCode() % size;
return Math.Abs(position);
// int hashValue = 0;
// for (int i = 0; i < key.Length; i++) {
// hashValue = (hashValue + (int)key[i] * i) % this.data.Length;
// }
// return hashValue;
}
}
Csharp
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