简书 賈小強
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package com.lab1.test3;

import java.util.LinkedList;
import java.util.Queue;

public class SequentailSearchST<Key, Value> {
    private Node first;
    private int n;

    private class Node {
        Key key;
        Value value;
        Node next;

        public Node(Key key, Value value, Node next) {
            this.key = key;
            this.value = value;
            this.next = next;
        }

    }

    public void delete(Key key) {
        Node x = first;
        Node last = null;
        while (x != null) {
            if (key.equals(x.key)) {
                last.next = x.next;
                n--;
            } else {
                last = x;
            }
            x=x.next;
        }
    }

    public Iterable<Key> keys() {
        Queue<Key> queue = new LinkedList<>();
        for (Node x = first; x != null; x = x.next) {
            queue.add(x.key);
        }
        return queue;
    }

    public Value get(Key key) {
        for (Node x = first; x != null; x = x.next) {
            if (key.equals(x.key)) {
                return x.value;
            }
        }
        return null;
    }

    public boolean contains(Key key) {
        return get(key) != null;
    }

    public boolean isEmpty() {
        return n == 0;
    }

    public int size() {
        return n;
    }

    public void put(Key key, Value value) {
        for (Node x = first; x != null; x = x.next) {
            if (key.equals(x.key)) {
                x.value = value;
                return;
            }
        }
        first = new Node(key, value, first);
        n++;
    }

    public static void main(String[] args) {
        SequentailSearchST<String, Integer> st = new SequentailSearchST<>();
        String test = "S E A R C H E X A M P L E";
        String[] keys = test.split(" ");
        for (int i = 0; i < keys.length; i++) {
            st.put(keys[i], i);
        }
        System.out.println("size         = " + st.size());
        System.out.println("isEmpty      = " + st.isEmpty());
        System.out.println("contains     = " + st.contains("S"));
        st.delete("S");
        System.out.println("contains     = " + st.contains("S"));
        for (String key : st.keys()) {
            System.out.println(key + " " + st.get(key));
        }
    }

}

输出

size         = 10
isEmpty      = false
contains     = true
contains     = false
L 11
P 10
M 9
X 7
H 5
C 4
R 3
A 8
E 12

Happy learning !!