using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using System.Threading;

namespace AoC {
    
    internal class Day9 {
        
        private const int preamble = 25;
        
        internal void Solve() {
            var numbers = File.ReadAllText("day9/input")
                .Split("\n", StringSplitOptions.RemoveEmptyEntries)
                .Select(long.Parse)
                .ToList();

            bool ExistTwo(ISet<long> current, long target) => 
                current.Any(c => current.Contains(target - c));

            Queue<long> currentQueue = new Queue<long>();
            ISet<long> currentSet = new HashSet<long>();
            numbers.Take(preamble).ToList().ForEach(i => {
                currentQueue.Enqueue(i);
                currentSet.Add(i);
            });

            foreach (var n in numbers.Skip(preamble)) {
                if (!ExistTwo(currentSet, n)) {
                    Console.WriteLine(n);
                    break;
                }
            
                long firstInserted = currentQueue.Dequeue();
                currentQueue.Enqueue(n);
                currentSet.Remove(firstInserted);
                currentSet.Add(n);
            }
            
            // part two
            const long contiguousNumber = 69316178;

            long sum = 0;
            Queue<long> contiguousQueue = new Queue<long>();
            foreach (var n in numbers) {
                if (sum < contiguousNumber) {
                    contiguousQueue.Enqueue(n);
                    sum += n;
                }
                while (sum > contiguousNumber) {
                    sum -= contiguousQueue.Dequeue();
                }
                if (sum == contiguousNumber) {
                    long res = contiguousQueue.Min() + contiguousQueue.Max();
                    Console.WriteLine(res);
                    break;
                }
            }
        }
    }
}