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package com.todd.nowcoder;

import java.util.ArrayList;

import java.util.HashMap;

/**

* @author think

* @date 2020/9/26

*/

public class NC93 {

/**

* lru design

* @param operators int整型二维数组 the ops

* @param k int整型 the k

* @return int整型一维数组

*/

public int[] LRU (int[][] operators, int k) {

LRU lru = new LRU();

ArrayList<Integer> ans = new ArrayList<>();

for (int i = 0; i < k; i++) {

if (operators[i][0] == 1) {

lru.set(operators[i][1], operators[i][2]);

} else if (operators[i][0] == 2) {

int value = lru.get(operators[i][1]);

ans.add(value);

}

}

return ans.stream().mapToInt(Integer::valueOf).toArray();

}

class LRU {

class Node {

int key;

int value;

Node next;

Node pre;

public Node(int key, int value) {

this.key = key;

this.value = value;

}

}

private HashMap<Integer, Node> map;

private Node head;

private Node tail;

public LRU() {

map = new HashMap<>();

}

public void set(int key, int value) {

Node node = map.get(key);

if (node == null) {

node = new Node(key, value);

appendHead(node);

map.put(key, node);

} else {

node.value = value;

removeNode(node);

appendHead(node);

}

}

public int get(int key) {

Node node = map.get(key);

if (node == null) {

return -1;

} else {

int val = node.value;

removeNode(node);

appendHead(node);

return val;

}

}

public void appendHead (Node node) {

if (head == null && tail == null) {

head = node;

tail = node;

} else {

node.next = head;

head.pre = node;

head = node;

}

}

public void removeNode (Node node) {

if (head == tail) {

head = tail = null;

} else if (head == node) {

head = head.next;

head.pre = null;

} else if (tail == node) {

tail = tail.pre;

tail.next = null;

} else {

node.pre.next = node.next;

node.next.pre = node.pre;

node.next = null;

node.pre = null;

}

}

}

}