2021.10.06 - 115.设计LRU缓存结构

• 1. 题目
• 2. 思路
• • (1) HashMap+队列
• 3. 代码

• 利用HashMap存储键值对数据，利用队列控制数据的更替。

import java.util.*;

public class Test {
    public static void main(String[] args) {
    }
}

class Solution {
    public int[] LRU(int[][] operators, int k) {
        Map map = new HashMap<>();
        Queue queue = new linkedList<>();
        int[] res = new int[operators.length];
        int index = 0;
        for (int i = 0; i < operators.length; i++) {
            switch (operators[i][0]) {
                case 1:
                    map.put(operators[i][1], operators[i][2]);
                    queue.offer(operators[i][1]);
                    if (queue.size() > k) {
                        map.remove(queue.poll());
                    }
                    break;
                case 2:
                    if (map.containsKey(operators[i][1])) {
                        res[index++] = map.get(operators[i][1]);
                        queue.remove(operators[i][1]);
                        queue.offer(operators[i][1]);
                    } else {
                        res[index++] = -1;
                    }
                    break;
            }
        }
        return Arrays.copyOfRange(res, 0, index);
    }
}