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

namespace AoC {
    
    internal class Day6 {

        internal void Solve() {
            var readLines = File.ReadAllText("day6/input").Split("\n\n", StringSplitOptions.RemoveEmptyEntries);
            
            static ISet<char> UniqueCharactersExceptNewline(string s) => s.Where(c => c != '\n').ToImmutableHashSet();
            int part1 = readLines.Select(UniqueCharactersExceptNewline).Sum(s => s.Count);
            
            Console.WriteLine(part1);
            
            static IEnumerable<IImmutableSet<char>> GroupToUniqueCharacters(string s) => s
                .Split('\n', StringSplitOptions.RemoveEmptyEntries)
                .Select(s => s.ToImmutableHashSet());
            
            static IImmutableSet<char> Intersection(IImmutableSet<char> first, IImmutableSet<char> second) =>
                first.Intersect(second);
            
            static IImmutableSet<char> IntersectAll(IEnumerable<IImmutableSet<char>> group) => group
                .Skip(1)
                .Aggregate(group.First(), Intersection);
            
            int part2 = readLines
                .Select(GroupToUniqueCharacters)
                .Select(IntersectAll)
                .Sum(s => s.Count);

            Console.WriteLine(part2);
        }
    }
}