public static int FirstPart(string filename)
{
var lines = ReadInputs.ReadAllInts(ReadInputs.GetFullPath(filename)).OrderBy(l => l).ToList();
var numOfOnes = 0;
var numOfThrees = 0;
var currentVoltage = 0;
var myVoltage = lines[lines.Count - 1] + 3;
foreach (var line in lines)
{
if (line - currentVoltage == 1)
{
numOfOnes++;
}
else if (line - currentVoltage == 3)
{
numOfThrees++;
}
currentVoltage = line;
}
return(numOfOnes * (numOfThrees + 1));
}
/// <summary>
/// Method to be run to ge the 2nd part of the solution.
/// Find three numbers in list that give a sum of 2020
/// </summary>
/// <param name="filename"></param>
/// <returns></returns>
public static int SecondPart(string filename)
{
var numbers = ReadInputs.ReadAllInts(filename);
for (int i = 0; i < numbers.Count; i++)
{
for (int j = 0; j < i; j++)
{
if (numbers[i] + numbers[j] > 2020)
{
continue; // if two numbers are greater than 2020, no sense trying out the 3rd.
}
for (int k = 0; k < j; k++)
{
if (numbers[i] + numbers[j] + numbers[k] == 2020)
{
return(numbers[i] * numbers[j] * numbers[k]);
}
}
}
}
throw new Exception("No sequence found.");
}