LeetCode算法学习笔记 - Day11

跟着网上的文章写了一遍哈希表的实现，本质上存储结构还是链表，所以有链表基础的同学就很容易上手了
主要流程就是根据key来进行哈希桶的分配，每个桶内有一个链表，分配完桶就进行正常的链表操作即可

public class Node {

    // key、value模拟键值对的数据
    public Integer key;
    public String value;

    // 下一节点的引用
    public Node next;

    public Node() {

    }

    public Node(int key, String value) {
        this.key = key;
        this.value = value;
    }

}

public class linkedList {
    private Node root;

    public linkedList(Node node){
        this.root = node;
    }

    
    public void add(int key,String value){
        Node node = root;
        while (node.next != null){
            if (node.next.key == key){
                return;
            }
            node = node.next;
        }
        node.next = new Node(key,value);
    }

    
    public boolean delete(int key){
        Node node = root;
        if (root.key == key){
            root = root.next;
            return true;
        }
        while (node.next != null){
            if (node.next.key == key){
                node.next = node.next.next;
                return true;
            }
            node = node.next;
        }
        return false;
    }

    
    public String get(int key){
        if (root.key == key){
            return root.value;
        }
        Node node = root;
        while (node.next != null){
            if (node.next.key == key){
                return node.next.value;
            }
            node = node.next;
        }
        return null;
    }

    
    public void show(){
        Node node = root;
        while (node != null){
            System.out.println(node.value);
            node = node.next;
        }
    }
}

public class HashTable {
    private linkedList[] lists; //这个linkedList是自己写的类不是自带的那个linkedList
    private int size;

    
    public HashTable(int size){
        this.size = size;
        lists = new linkedList[size];
    }

    
    public void put(int key,String value){
        int i = key % size;
        if (lists[i] == null){
            lists[i] = new linkedList(new Node(key,value));
        }else {
            lists[i].add(key,value);
        }
    }

    
    public boolean delete(int key){
        int i = key % size;
        if (lists[i] != null){
            return lists[i].delete(key);
        }
        return false;
    }

    
    public String get(int key){
        int i = key % size;
        if (lists[i] != null){
            return lists[i].get(key);
        }
        return null;
    }

    
    public void show(){
        for (int i = 0; i < size; i++) {
            if (lists[i] != null){
                lists[i].show();
            }
        }
    }
}

public class main {
    public static void main(String[] args) {
        HashTable hashTable = new HashTable(10);
        hashTable.put(1,"TestA1");
        hashTable.put(2,"TestA2");
        hashTable.put(3,"TestA3");
        hashTable.put(11,"TestB1");
        hashTable.put(12,"TestB2");
        hashTable.put(13,"TestB3");
        hashTable.delete(1);
        hashTable.delete(11);
        System.out.println(hashTable.get(2));
        System.out.println(hashTable.get(3));
        hashTable.show();
    }
}