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| 1 | +import java.util.ArrayList; |
| 2 | +import java.util.List; |
| 3 | +public class HashMap<Key, Value> { |
| 4 | + |
| 5 | + public class Node<Key, Value> { |
| 6 | + Key key; |
| 7 | + Value value; |
| 8 | + |
| 9 | + Node<Key, Value> next; |
| 10 | + |
| 11 | + public Node(Key k, Value v) { |
| 12 | + this.key = k; |
| 13 | + this.value = v; |
| 14 | + this.next = null; |
| 15 | + } |
| 16 | + } |
| 17 | + |
| 18 | + List<Node<Key, Value> > Map; |
| 19 | + private int N; |
| 20 | + |
| 21 | + public HashMap(int n) { |
| 22 | + N = n; |
| 23 | + Map = new ArrayList<Node<Key, Value> >(N + 1); |
| 24 | + |
| 25 | + for (int i = 0; i < n; i++) |
| 26 | + Map.add(null); |
| 27 | + |
| 28 | + } |
| 29 | + |
| 30 | + public void put(Key k, Value v) { |
| 31 | + int loc = (Math.abs(k.hashCode())) % N; |
| 32 | + |
| 33 | + Node<Key, Value> newNode = new Node<Key, Value>(k, v); |
| 34 | + newNode.next = Map.get(loc); |
| 35 | + Map.set(loc, newNode); |
| 36 | + } |
| 37 | + |
| 38 | + public Value get(Key k) { |
| 39 | + int loc = Math.abs(k.hashCode()) % N; |
| 40 | + |
| 41 | + Node<Key, Value> crawl = Map.get(loc); |
| 42 | + while (crawl != null) { |
| 43 | + if (crawl.key == k) |
| 44 | + return crawl.value; |
| 45 | + crawl = crawl.next; |
| 46 | + } |
| 47 | + |
| 48 | + return null; |
| 49 | + } |
| 50 | + |
| 51 | + public boolean contains(Key k) { |
| 52 | + int loc = Math.abs(k.hashCode()) % N; |
| 53 | + |
| 54 | + Node<Key, Value> crawl = Map.get(loc); |
| 55 | + while (crawl != null) { |
| 56 | + if (crawl.key == k) |
| 57 | + return true; |
| 58 | + crawl = crawl.next; |
| 59 | + } |
| 60 | + return false; |
| 61 | + } |
| 62 | + |
| 63 | + public static void main(String[] args) { |
| 64 | + HashMap <String, Integer> Map = new HashMap<>(5); |
| 65 | + |
| 66 | + Map.put("abc", 123); |
| 67 | + Map.put("brt", 345); |
| 68 | + Map.put("cio", 678); |
| 69 | + |
| 70 | + if (Map.contains("brt") == true) |
| 71 | + System.out.println(Map.get("brt")); |
| 72 | + else |
| 73 | + System.out.println("Key doesn't exists"); |
| 74 | + |
| 75 | + if (Map.contains("ger") == true) |
| 76 | + System.out.println(Map.get("ger")); |
| 77 | + else |
| 78 | + System.out.println("Key doesn't exists"); |
| 79 | + |
| 80 | + } |
| 81 | +} |
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