public int Part1()
{
string input = InputUtils.GetDayInputString(16);
List <int> inputList = input.ToCharArray().Select(p => int.Parse(p.ToString())).ToList();
List <int> newList = new List <int>();
for (int phase = 0; phase < 100; phase++)
{
for (int i = 0; i < inputList.Count; i++)
{
// calculate position i in new list, which is
// the sum of all of the previous values
int sum = 0;
for (int j = 0; j < inputList.Count; j++)
{
sum += GetMultiplier(i + 1, j) * inputList[j];
}
newList.Add(Math.Abs(sum) % 10);
}
inputList = new List <int>(newList);
newList.Clear();
}
StringBuilder sb = new StringBuilder();
for (int o = 0; o < 8; o++)
{
sb.Append(inputList[o]);
}
return(int.Parse(sb.ToString()));
}
public int Part2()
{
var input = InputUtils.GetDayInputString(2018, 8);
List <int> inputInts = input.Split(' ').Select(p => int.Parse(p)).ToList();
Node root = BuildTree(inputInts);
int sum = GetNodeValue(root);
return(sum);
}
public int Part1()
{
var input = InputUtils.GetDayInputString(2018, 8);
List <int> inputInts = input.Split(' ').Select(p => int.Parse(p)).ToList();
Node root = BuildTree(inputInts);
// add up the sum
int sum = GetMetadataSum(root);
return(sum);
}
public int Part2()
{
string input = InputUtils.GetDayInputString(16);
int offset = 5970417;
List <int> oo = input.ToCharArray().Select(p => int.Parse(p.ToString())).ToList();
List <int> originalInput = new List <int>();
for (int c = 0; c < 10000; c++)
{
originalInput.AddRange(oo);
}
for (int phase = 0; phase < 100; phase++)
{
int sum = 0;
// we only need to check the tail, and they are all 1s in
// the repeating pattern at that point
// from the end, we take each digit going backwards
// and use it as part of the sum for the next digit,
// because the repeating pattern makes for zeroes all the
// way up to the point we are calculating
for (int i = 1; i < originalInput.Count - offset + 1; i++)
{
sum += originalInput[originalInput.Count - i];
sum = Math.Abs(sum) % 10;
// since we're going backwards, just replace the
// slot we just used with what we just computed
originalInput[originalInput.Count - i] = sum;
}
}
StringBuilder sb = new StringBuilder();
for (int o = 0; o < 8; o++)
{
sb.Append(originalInput[offset + o]);
}
return(int.Parse(sb.ToString()));
}
public int Part2()
{
string input = InputUtils.GetDayInputString(2018, 5);
var letters = Enumerable.Range((int)'a', 26).Select(p => (char)p).ToList();
int smallest = int.MaxValue;
foreach (var letter in letters)
{
// remove letter
string newInput = input.Replace(letter.ToString(), String.Empty);
newInput = newInput.Replace(char.ToUpper(letter).ToString(), String.Empty);
int collapsed = CollapsePolymer(newInput);
if (collapsed < smallest)
{
smallest = collapsed;
}
}
return(smallest);
}
public int Part1()
{
string input = InputUtils.GetDayInputString(2018, 5);
return(CollapsePolymer(input));
}
