static Object PartA()
{
var input = ReadIndata.Strings(inputPath);
LinkedList <int> circularBuffer = new LinkedList <int>(input[0].Select(x => (int)x - '0'));
int n = circularBuffer.Count;
var valueToCup = new List <LinkedListNode <int> >(n + 1);
for (int i = 0; i <= n; i++)
{
valueToCup.Add(null);
}
var pos = circularBuffer.First;
for (int i = 1; i <= n; i++)
{
valueToCup[pos.Value] = pos;
pos = pos.Next;
}
StepCrabCups(circularBuffer, valueToCup, 100);
pos = circularBuffer.Find(1);
var pp = pos.NextOrFirst();
string ans = "";
while (pp != pos)
{
ans += pp.Value.ToString();
pp = pp.NextOrFirst();
}
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Ints(inputPath);
input.Add(0);
input.Add(input.Max() + 3);
input.Sort();
long ans = 1;
int i = 0;
int z = input.Count;
var combs = new int[] { 0, 1, 1, 2, 4, 7 };
while (i < z - 1)
{
int n = 1;
while ((i + n < z) && (input[i + n] - input[i + n - 1] == 1))
{
n++;
}
ans *= combs[n];
i += n;
}
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
var input = ReadIndata.Strings(inputPath);
Position pos = new Position();
int dirIdx = 1;
foreach (var s in input)
{
char c = s[0];
int n = int.Parse(s.Substring(1));
if (c == 'F')
{
pos += CoordsXY.directions4[Utils.Modulo(dirIdx, 4)] * n;
}
else if (c == 'L')
{
dirIdx -= n / 90;
}
else if (c == 'R')
{
dirIdx += n / 90;
}
else
{
pos += CoordsXY.directions4[cardinals.IndexOf(c)] * n;
}
}
int ans = pos.ManhattanDistance();
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Strings(inputPath);
LinkedList <int> circularBuffer = new LinkedList <int>(input[0].Select(x => (int)x - '0'));
int n = 1_000_000;
for (int i = 10; i <= n; i++)
{
circularBuffer.AddLast(i);
}
var valueToCup = new List <LinkedListNode <int> >(n + 1);
for (int i = 0; i <= n; i++)
{
valueToCup.Add(null);
}
var pos = circularBuffer.First;
for (int i = 1; i <= n; i++)
{
valueToCup[pos.Value] = pos;
pos = pos.Next;
}
StepCrabCups(circularBuffer, valueToCup, 10_000_000);
pos = circularBuffer.Find(1);
var p = pos.NextOrFirst();
var pp = p.NextOrFirst();
long ans = p.Value * (long)pp.Value;
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
var input = ReadIndata.Strings(inputPath);
Regex re = new Regex(@"(e|se|sw|w|nw|ne)");
foreach (var s in input)
{
var pos = new Position();
foreach (Match match in re.Matches(s))
{
pos += CoordsHex.directionsWide[match.Value];
}
if (black.Contains(pos))
{
black.Remove(pos);
}
else
{
black.Add(pos);
}
}
int ans = black.Count();
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Strings(inputPath);
Position wpos = new Position(10, 1);
Position spos = new Position();
foreach (var s in input)
{
char c = s[0];
int n = int.Parse(s.Substring(1));
if (c == 'F')
{
spos += wpos * n;
}
else if (c == 'L')
{
wpos = Position.Rotate4Steps(wpos, -n / 90);
}
else if (c == 'R')
{
wpos = Position.Rotate4Steps(wpos, n / 90);
}
else
{
wpos += CoordsXY.directions4[cardinals.IndexOf(c)] * n;
}
}
int ans = spos.ManhattanDistance();
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
var input = ReadIndata.Strings(inputPath);
string mask = "";
var mem = new Dictionary <int, long>();
foreach (var s in input)
{
var t = s.Split("[] =".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
if (t.Contains("mask"))
{
mask = t[1];
}
else
{
var a = Convert.ToString(long.Parse(t[2]), 2).PadLeft(bits, '0');
var b = "";
for (int i = 0; i < bits; i++)
{
b += mask[i] == 'X' ? a[i] : mask[i];
}
mem[int.Parse(t[1])] = Convert.ToInt64(b, 2);
}
}
long ans = mem.Select(x => x.Value).Sum();
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
var input = ReadIndata.Longs(inputPath);
long ans = 0;
bool found = true;
const int n = 25;
int t = n;
while (found)
{
found = false;
ans = input[t];
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
if ((i != j) && (input[t - n + i] + input[t - n + j] == ans))
{
found = true;
}
}
}
t++;
}
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
List <long> input = ReadIndata.Longs(inputPath);
input.Sort();
long ans = 0;
for (int i = 0; i < input.Count; i++)
{
for (int j = 0; j < input.Count; j++)
{
if (j != i)
{
long a = input[i];
long b = input[j];
long c = 2020 - a - b;
if (input.Contains(c))
{
ans = a * b * c;
break;
}
}
}
}
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Longs(inputPath);
long ans = 0;
const long tgt = 167829540;
int t = 0;
while (ans <= 0)
{
long sum = 0;
int n = 0;
for (n = 0; n < 2 || sum < tgt; n++)
{
sum += input[t + n];
}
if (sum == tgt)
{
var r = input.Skip(t).Take(n).ToList();
ans = r.Min() + r.Max();
}
t++;
}
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
List <string> input = ReadIndata.Strings(inputPath);
int ans = 0;
Dictionary <char, int> dict = new Dictionary <char, int>();
int n = 0;
foreach (string s in input)
{
if (s == "")
{
ans += dict.Where(x => x.Value == n).Count();
dict = new Dictionary <char, int>();
n = 0;
}
else
{
foreach (char c in s)
{
if (!dict.ContainsKey(c))
{
dict[c] = 0;
}
dict[c]++;
}
n++;
}
}
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Strings(inputPath);
var computer = new Computer(input);
computer.Run();
int ans = 0;
foreach (int offs in computer.orderVisited)
{
var c = new Computer(computer.source);
var i = c.program[offs];
var n = i.opCode.name;
if (n != "acc")
{
i.opCode = c.instructionSet[n == "jmp" ? "nop" : "jmp"];
c.program[offs] = i;
if (c.Run())
{
ans = c.acc;
break;
}
}
}
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Ints(inputPath);
int ans = MemoryGame(input, 30000000);
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
var input = ReadIndata.Ints(inputPath);
int ans = 0;
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
List <string> input = ReadIndata.Strings(inputPath);
HashSet <int> ids = GetIds(input);
int ans = ids.Max();
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
List <string> input = ReadIndata.Strings(inputPath);
HashSet <int> ids = GetIds(input);
int ans = ids.Where(x => !ids.Contains(x + 1) && ids.Contains(x + 2)).Min() + 1;
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
var input = ReadIndata.Strings(inputPath);
var c = new Computer(input);
c.Run();
var ans = c.acc;
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
List <string> input = ReadIndata.Strings(inputPath);
long ans = CalcTrees(input, 1, 1);
ans *= CalcTrees(input, 1, 3);
ans *= CalcTrees(input, 1, 5);
ans *= CalcTrees(input, 1, 7);
ans *= CalcTrees(input, 2, 1);
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
var input = ReadIndata.Strings(inputPath);
int cardPk = int.Parse(input[0]);
int doorPk = int.Parse(input[1]);
int cardLoopSize = CalcLoopSize(7, cardPk);
//int doorLoopSize = CalcLoopSize(7, doorPk);
long ans = Calc(doorPk, cardLoopSize);
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Strings(inputPath);
long ans = 0;
foreach (string s in input)
{
ans += Calc(s, true);
}
//foreach (string s in input)
// ans += Calc(s, EvaluateB);
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
// Day 22: Crab Combat - Play card game, first simple, then with recursion and more
static List <int> ReadInput(string path)
{
var strs = ReadIndata.Strings(path);
var list = new List <int>();
foreach (var line in strs)
{
if (line.Length > 0 && char.IsDigit(line[0]))
{
list.Add(int.Parse(line));
}
}
return(list);
}
static void ReadInput(string path)
{
var input = ReadIndata.Strings(path);
void AddFoodToItem(Dictionary <string, HashSet <int> > col, string key, int f)
{
if (!col.ContainsKey(key))
{
col[key] = new HashSet <int>();
}
col[key].Add(f);
}
void AddItemToFood(Dictionary <int, HashSet <string> > col, int f, string item)
{
if (!col.ContainsKey(f))
{
col[f] = new HashSet <string>();
}
col[f].Add(item);
}
int food = 0;
foreach (string s in input)
{
var v = s.Split("(contains");
var iv = v[0].Split(" ", StringSplitOptions.RemoveEmptyEntries);
var av = v[1].Split(" ,)".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
{
foreach (string ingr in iv)
{
ingredients.Add(ingr);
AddItemToFood(foodIngredients, food, ingr);
AddFoodToItem(foodsWithIngredient, ingr, food);
}
}
{
foreach (string aller in av)
{
allergenes.Add(aller);
AddItemToFood(foodAllergenes, food, aller);
AddFoodToItem(foodsWithAllergen, aller, food);
}
}
food++;
}
}
// Day 03: Toboggan Trajectory - Check occurrences in 2D character map
static Object PartA()
{
List <string> input = ReadIndata.Strings(inputPath);
int ans = 0;
int c = 0;
for (int r = 0; r < input.Count; r++)
{
if (input[r][c % input[0].Count()] == '#')
{
ans++;
}
c += 3;
}
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
var input = ReadIndata.Ints(inputPath);
input.Add(0);
input.Add(input.Max() + 3);
input.Sort();
var d = new int[] { 0, 0, 0, 0 };
for (int i = 1; i < input.Count; i++)
{
d[input[i] - input[i - 1]]++;
}
int ans = d[1] * d[3];
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Strings(inputPath);
Map m = Map.Build(input);
Map m2 = new Map(m);
int n = 0;
do
{
m = m2;
m2 = StepMapB(m);
n++;
}while (m != m2);
int ans = m.data.Cast <char>().Where(x => x == '#').Count();
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
static Object PartA()
{
List <int> input = ReadIndata.Ints(inputPath);
input.Sort();
int ans = 0;
foreach (int a in input)
{
int b = 2020 - a;
if (input.Contains(b))
{
ans = a * b;
break;
}
}
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Strings(inputPath);
string mask = "";
var mem = new Dictionary <long, long>();
foreach (var s in input)
{
var t = s.Split("[] =".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
if (t.Contains("mask"))
{
mask = t[1];
}
else
{
var a = Convert.ToString(long.Parse(t[1]), 2).PadLeft(bits, '0');
var b = "";
var offs = new List <long>()
{
0
};
for (int i = 0; i < bits; i++)
{
var m = mask[i];
if (m == 'X')
{
offs.Add(1L << bits - 1 - i);
}
b += m == 'X' ? '0' : (m == '1' ? '1' : a[i]);
}
var membase = Convert.ToInt64(b, 2);
var value = long.Parse(t[2]);
foreach (var z in Algorithms.GetCombinations(offs))
{
mem[membase + z.Sum()] = value;
}
}
}
long ans = mem.Select(x => x.Value).Sum();
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
// Day 13: Shuttle Search - Modular arithmetic & The Chinese Remainder Theorem (CRT)
static Object PartA()
{
var input = ReadIndata.Strings(inputPath);
List <int> ids = input[1].Split(',').Where(x => x != "x").Select(x => int.Parse(x)).ToList();
int minutes = int.Parse(input[0]);
int min = int.MaxValue;
int ans = 0;
foreach (int i in ids)
{
int a = i - (minutes % i);
if (a < min)
{
min = a;
ans = a * i;
}
}
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}
static Object PartB()
{
var input = ReadIndata.Strings(inputPath);
List <int> ids = new List <int>();
List <int> offs = new List <int>();
int i = 0;
foreach (string s in input[1].Split(','))
{
if (s != "x")
{
int id = int.Parse(s);
ids.Add(id);
offs.Add(id - i);
}
i++;
}
long ans = Utils.CRT(ids, offs);
Console.WriteLine("Part B: Result is {0}", ans);
return(ans);
}
// Day 06: Custom Customs - Parse groups and questions, perform some and/or logic
static Object PartA()
{
List <string> input = ReadIndata.Strings(inputPath);
int ans = 0;
HashSet <char> set = new HashSet <char>();
foreach (string s in input)
{
if (s == "")
{
ans += set.Count;
set = new HashSet <char>();
}
else
{
set.UnionWith(s.ToHashSet());
}
}
ans += set.Count;
Console.WriteLine("Part A: Result is {0}", ans);
return(ans);
}