코딩테스트 큐: 상담 창구 대기열 명령 처리

function createQueue() {
    let items = [];
    let head = 0;
    return {
        enqueue(value) {
            items.push(value);
        },
        dequeue() {
            if (head === items.length) {
                return {
                    done : true
                };
            }
            const value = items[head];
            items[head] = undefined;
            head += 1;
            if (head === items.length) {
                items = [];
                head = 0;
            } else if (head >= 1024 && head * 2 >= items.length) {
                items = items.slice(head);
                head = 0;
            }
            return {
                done : false, value
            };
        },
        size() {
            return items.length - head;
        },
    };
}
function solve(input) {
    const text = input.trim();
    if (! text) {
        return '';
    }
    const lines = text.split(/\r?\n/);
    const count = Number(lines[0]);
    const queue = createQueue();
    const output = [];
    for (let i = 1; i <= count; i++) {
        const[command, name] = lines[i].split(' ');
        if (command === 'ARRIVE') {
            queue.enqueue(name);
        } else if (command === 'CALL') {
            const result = queue.dequeue();
            output.push(result.done ? 'EMPTY' : result.value);
        } else if (command === 'COUNT') {
            output.push(String(queue.size()));
        }
    }
    return output.join('\n');
}

from collections import deque
def solve(input):
    lines=input.splitlines()
    queue,output=deque(),[]
    for line in lines[1:1+int(lines[0])]:
        parts=line.split(' ',1)
        if parts[0]=='ARRIVE': queue.append(parts[1])
        elif parts[0]=='CALL': output.append(queue.popleft() if queue else 'EMPTY')
        else: output.append(str(len(queue)))
    return '\n'.join(output)

import java.util.*;
class Solution {
    public String solve(String input) {
        String[] lines = input.split("\r?\n");
        int count = Integer.parseInt(lines[0]);
        Queue < String > q = new ArrayDeque < >();
        List < String > out = new ArrayList < >();
        for (int i = 1; i <= count; i++) {
            String[] p = lines[i].split(" ", 2);
            if (p[0].equals("ARRIVE")) q.add(p[1]);
            else if (p[0].equals("CALL")) out.add(q.isEmpty() ? "EMPTY" : q.remove());
            else out.add(String.valueOf(q.size()));
        }
        return String.join("\n", out);
    }
}

#include <sstream>
#include <string>
#include <queue>
std::string solve(const std::string & input) {
    std::istringstream in(input);
    int count;
    in >> count;
    std::queue < std::string > q;
    std::string command, name, out;
    bool first = true;
    for (int i = 0; i < count; i++) {
        in >> command;
        if (command == "ARRIVE") {
            in >> name;
            q.push(name);
        } else {
            std::string row;
            if (command == "CALL") {
                row = q.empty() ? "EMPTY" : q.front();
                if (! q.empty()) q.pop();
            } else row = std::to_string(q.size());
            if (! first) out += "\n";
            first = false;
            out += row;
        }
    }
    return out;
}

using System;
using System.Collections.Generic;
public class Solution {
    public string Solve(string input) {
        string[] lines = input.Replace("\r\n", "\n").Split('\n');
        int count = int.Parse(lines[0]);
        var q = new Queue < string >();
        var output = new List < string >();
        for (int i = 1; i <= count; i++) {
            string[] p = lines[i].Split(new char[] {
                ' '
            }, 2);
            if (p[0] == "ARRIVE") q.Enqueue(p[1]);
            else if (p[0] == "CALL") output.Add(q.Count == 0 ? "EMPTY" : q.Dequeue());
            else output.Add(q.Count.ToString());
        }
        return string.Join("\n", output);
    }
}