单链表实现LRU缓存

Author: randian666

src/main/java/com/algorithm/study/demo/LRUCache/LRULinked.java

@@ -0,0 +1,97 @@
+package com.algorithm.study.demo.LRUCache;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * 单链表实现LRU缓存
+ * @Author: liuxun
+ * @CreateDate: 2019/1/23 下午4:03
+ * @Version: 1.0
+ */
+public class LRULinked<K,V>{
+    private final Map<K, V> cacheMap = new HashMap<>();
+
+    private Node<K, V> root;
+    private int cacheSize;
+    private int size;
+    public LRULinked(int cacheSize){
+        this.cacheSize=cacheSize;
+    }
+
+    /**
+     * 插入头结点
+     * @param value
+     */
+    public void put(K key,V value){
+        Node<K, V> node=new Node<K, V>(key,value);
+        if (size==cacheSize){//容量满了删除尾节点
+            Node<K, V> temp=root.next;
+            if (temp==null){
+                root=null;
+                size--;
+            }else{
+                Node<K, V> current=root;
+                while (temp.next!=null){
+                    current=temp;
+                    temp=temp.next;
+                }
+                current.next=null;
+                size--;
+            }
+        }
+        node.next=root;
+        root=node;
+        size++;
+    }
+    public V get(K key){
+        for (Node<K,V> node = root; node!=null; node=node.next){
+            if (node.next.key.equals(key)){
+                Node<K, V> nodeNew=new Node<K, V>(node.next.key,node.next.value);
+                node.next=node.next.next;
+                size--;
+                this.put(nodeNew.key,nodeNew.value);//查找的节点放到头结点
+                break;
+            }
+        }
+        return cacheMap.get(key);
+    }
+    @Override
+    public String toString(){
+        StringBuilder sb=new StringBuilder();
+        int j=0;
+        Node<K, V> temp=root;
+        while (j<size){
+            sb.append(temp.value);
+            temp= temp.next;//找到最后一个结点
+            j++;
+        }
+        return sb.toString();
+    }
+
+    public static class Node<K, V>{
+        private K key;
+        private V value;
+        private Node<K, V> next;
+        public Node(K key, V value){
+            this.key=key;
+            this.value=value;
+        }
+    }
+
+    public static void main(String[] args) {
+        LRULinked<String,String> linked=new LRULinked<>(3);
+        linked.put("a","a");
+        linked.put("b","b");
+        linked.put("c","c");
+        linked.get("a");
+        linked.put("d","d");
+        System.out.println(linked.size);
+        System.out.println(linked.toString());
+        System.out.println(linked.toString());
+        System.out.println(linked.size);
+
+
+
+    }
+}