public long ExecutePartOne(string inputFile, int index = 25)
{
var input = ArraysAndLists.StringArrayToLongArray(General.GetDataFromInputFileAsStringArray(inputFile));
var currentIndex = index; // skip first
long checkingNumber;
foreach (var line in input.Skip(index))
{
var foundSum = false;
checkingNumber = line;
var preamble = input.Skip(currentIndex - index).Take(index);
foreach (var calc in preamble.Distinct())
{
var lookForNumber = checkingNumber - calc;
if (preamble.Any(x => x == lookForNumber))
{
foundSum = true;
break;
}
;
}
if (!foundSum)
{
return(checkingNumber);
}
currentIndex++;
}
return(0);
}
public long ExecutePartTwo(string inputFile, int index = 25)
{
var input = ArraysAndLists.StringArrayToLongArray(General.GetDataFromInputFileAsStringArray(inputFile));
var lookForNumber = ExecutePartOne(inputFile, index);
var validNumbers = input.Where(x => x < lookForNumber).Reverse();
for (int from = 0; from < validNumbers.Count(); from++)
{
var numberOfRecords = 1;
var list = validNumbers.Skip(from);
do
{
var sum = list.Take(numberOfRecords).Sum();
if (sum == lookForNumber)
{
return(list.Take(numberOfRecords).Min() + list.Take(numberOfRecords).Max());
}
else if (sum > lookForNumber)
{
break;
}
numberOfRecords++;
}while (numberOfRecords + from < validNumbers.Count());
}
return(0);
}