沃尔玛一个后端组的合同工OA面经_i++

lru cache的调用,


public static List<Integer> solve(int capacity,List<String> ar){


}



内部类直接粘贴到class里面,调用方法在外面。lru cach直接贴过去。耗时太久了

抓作弊的浏览器,另一台电脑用mac剪切板复制粘贴就可以

equals()判断字符串是否相等

required variable found value说明arraylist不能赋值,给array赋值再粘贴过去就可以

我写的不对的代码:


import java.util.*;
import java.io.*;
import java.math.*;




class Outcome {

/*
* Implement method/function with name 'solve' below.
* The function accepts following as parameters.
* 1. capacity is of type int.
* 2. ar is of type List<String>.
* return List<Integer>.
*/

private class Node {
Node prev;
Node next;
int key;
int value;

public Node(int key, int value) {
this.key = key;
this.value = value;
this.prev = null;
this.next = null;
}
}

private int capacity;
private HashMap<Integer,Node> hs = new HashMap<Integer,Node>();
private Node head = new Node(-1,-1);
private Node tail = new Node(-1,-1);

public Outcome() {
this.capacity = capacity;
tail.prev = head;
head.next = tail;
}

/*
* @param key: An integer
* @return: An integer
*/
public int get(int key) {
if (!hs.containsKey(key)) {
return -1;
}

//remove the selected node
Node curt = hs.get(key);
curt.prev.next = curt.next;
curt.next.prev = curt.prev;
//move_to_tail since it's visited
move_to_tail(curt);
//return
return hs.get(key).value;
}

/*
* @param key: An integer
* @param value: An integer
* @return: nothing
*/
public void put(int key, int value) {
//if exists, renew the key's value
if (get(key) != -1) {
hs.get(key).value = value;
return ;//
}
//if full, remove head.next in order to put in the new node
if (hs.size() == capacity) {
hs.remove(head.next.key);
head.next = head.next.next;
head.next.prev = head;
}
//new insert
Node insert = new Node(key,value);
hs.put(key,insert);
move_to_tail(insert);
}

private void move_to_tail(Node curt) {
curt.prev = tail.prev;
tail.prev = curt;
curt.prev.next = curt;
curt.next = tail;
}

public static List<Integer> solve(int capacity,List<String> ar){
//Write your code here
Outcome outcome = new Outcome();
outcome.capacity = capacity;
List<Integer> res = new LinkedList<>();

for (int i = 0; i < ar.size(); i++) {
if (ar.get(i) == "GET") {
Integer getRes = Integer.valueOf(outcome.get(Integer.valueOf(ar.get(i++))));
res.add(getRes);
}else if (ar.get(i) == "PUT") {
outcome.put(Integer.valueOf(ar.get(i++)), Integer.valueOf(ar.get(i++)));
}
}

return res; //return type "List<Integer>".
}

}

public class Main {
public static void main(String[] args) throws IOException {
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getProperty("OUTPUT_FILE_PATH")));
bufferedWriter.write("\n");
bufferedWriter.close();
bufferedWriter = new BufferedWriter(new FileWriter(System.getProperty("OUTPUT_FILE_PATH"),true));
int capacity = Integer.parseInt(bufferedReader.readLine().trim());

int arCount = Integer.parseInt(bufferedReader.readLine().trim());

List<String> ar = new ArrayList<>();

String[] artempItems = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");

for (int i = 0; i < arCount; i++) {
String arItem = artempItems[i];
ar.add(arItem);
}

List<Integer> outcome = Outcome.solve(capacity,ar);

for(int i=0;i<outcome.size();i++) {
bufferedWriter.write(outcome.get(i).toString());
if(i<outcome.size()-1)
bufferedWriter.write(" ");
}

bufferedWriter.newLine();

bufferedReader.close();
bufferedWriter.close();
}
}