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Copy pathLRUCache.java
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97 lines (86 loc) · 2.41 KB
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import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.Map;
/**
* 【工程】: LeetCode 包名: PACKAGE_NAME 类名: LRUCache
* 【作者】: liuyang
* 【时间】: 17/4/29 下午2:41
* 【题目】: LRU Cache
* 【内容】: 设计一个数据结构实现LRU缓存
* 【版本】: V1.0
* 【运行时间】:
* 【时间复杂度】:
* 【空间复杂度】:
* 【备注】: 能够实现所有操作的时间复杂度都是O(1)的么？
* 【思路】:
*/
public class LRUCache {
private LinkedHashMap<Integer, Integer> map;
private final int CAPACITY;
public LRUCache(int capacity) {
CAPACITY = capacity;
map = new LinkedHashMap<Integer, Integer>(capacity, 0.75f, true){
protected boolean removeEldestEntry(Map.Entry eldest) {
return size() > CAPACITY;
}
};
}
public int get(int key) {
return map.getOrDefault(key, -1);
}
public void put(int key, int value) {
map.put(key, value);
}
public static void main(String[] args) {
LRUCache t = new LRUCache(2);
System.out.println();
LinkedHashMap<Integer, Integer> tmp = new LinkedHashMap<>();
tmp.put(1, 1);
tmp.put(2, 2);
System.out.println(t);
}
}
/*
public class LRUCache {
private HashMap<Integer, Integer> map;
private LinkedList<Integer> list;
private int capacity;
public LRUCache(int capacity) {
this.capacity = capacity;
this.map = new HashMap<>();
this.list = new LinkedList<>();
}
public int get(int key) {
if (map.containsValue(key)) {
update(key);
return map.get(key);
} else {
return -1;
}
}
public void put(int key, int value) {
map.put(key, value);
if (map.containsKey(key)) {
update(key);
} else if (list.size() < capacity) {
list.addFirst(key);
} else {
list.pollLast();
list.addFirst(key);
}
}
public void update(int key) {
list.remove(key);
list.addFirst(key);
}
public static void main(String[] args) {
LRUCache t = new LRUCache(2);
System.out.println();
LinkedHashMap<Integer, Integer> tmp = new LinkedHashMap<>();
tmp.put(1, 1);
tmp.put(2, 2);
System.out.println(t);
}
}
*/