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Implement Hashmap in Java.
原理： Hashmap就是array of linkedlist，就是利用hash算法，算index之后，然后冲突了，就看后面有没有 Key Value pair 相等，如果相同，则覆盖，如果没有，则加在bucket的beginning。 源代码： http://developer.classpath.org/doc/java/util/HashMap-source.html
public class ImplementHashMap {class Node{String key;Integer val;Node next;public Node(String key, Integer val){this.key = key;this.val = val;}}private int size = 3;private Node[] array;public ImplementHashMap() {array = new Node[size];}public void put(String key, Integer value){int index = key.hashCode()%this.size;System.out.println("index is:"+index);Node node = array[index];while(node!=null) {if(node.key.equals(key)){node.val = value;return;} else {node = node.next;}}// add new entry to the beginning of the bucket;Node newnode = new Node(key,value);newnode.next = array[index];array[index] = newnode;return;}public Integer get(String key){int index = key.hashCode()%this.size;Node node = array[index];while(node!=null){if(node.key.equals(key)){return node.val;} else {node = node.next;}}return null;}public static void main(String[] args) {// TODO Auto-generated method stubImplementHashMap hashmap = new ImplementHashMap();hashmap.put("a", 2);System.out.println(hashmap.get("a"));hashmap.put("b", 5);System.out.println(hashmap.get("b"));hashmap.put("c", 7);System.out.println(hashmap.get("c"));hashmap.put("d", 8);System.out.println(hashmap.get("d"));hashmap.put("e", 9);System.out.println(hashmap.get("e"));hashmap.put("f", 10);System.out.println(hashmap.get("f"));}}index is:1
2
index is:2
5
index is:0
7
index is:1
8
index is:2
9
index is:0
10
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