우선 문제에 있는 테스트 케이스는 모두 통과했음
문제 : https://www.acmicpc.net/problem/1874
using System;using System.Collections.Generic;
namespace Boj1874{    class Program    {        static void Main(string[] args)        {            int n = int.Parse(Console.ReadLine());            var stack = new Stack<int>();            var log = new List<char>();            int[] values = new int[n];            for (int i = 0; i < n; i++)            {                values[i] = int.Parse(Console.ReadLine());            }            int pointer = 0;            int num = 1;
            while (true)            {                if (num <= n && stack.Count == 0)                {                    stack.Push(num);                    log.Add('+');                    num++;                }
                if (num > n && stack.Count == 0)                {                    break;                }                else if (num <= n && stack.Peek() != values[pointer])                {                    stack.Push(num);                    log.Add('+');                    num++;                }                else if (stack.Peek() == values[pointer])                {                    stack.Pop();                    log.Add('-');                    pointer++;
                }                else                {                    Console.WriteLine("NO");                    return;                }            }
            foreach (var c in log)            {                Console.WriteLine(c);            }        }    }}