public static Day03Result Part2()
{
const string path = Helpers.inputPath + @"\day03\input.txt";
IList <string> input = Helpers.GetFileAsLines(path);
IList <(int, int)> slopes = new List <(int, int)>
{
(1, 1),
(3, 1),
(5, 1),
(7, 1),
(1, 2)
};
IList <SlopeResult> slopeResults = slopes.Select(s => new SlopeResult
{
Dx = s.Item1,
Dy = s.Item2,
TreesHit = GetTreesHit(input, s.Item1, s.Item2)
}).ToList();
return(new Day03Result
{
Answer = slopeResults.Aggregate((long)1, (a, v) => a * v.TreesHit),
Details = new Day03Details
{
Height = input.Count,
Width = input[0].Length,
SlopeResults = slopeResults
}
});
}
//######################################################################
// Part 1 + 2 Solutions
//######################################################################
public static int Part1()
{
const string path = Helpers.inputPath + @"\day13\input.txt";
IList <string> inputs = Helpers.GetFileAsLines(path);
int arriveTime = int.Parse(inputs[0]);
Regex rx = new Regex("[0-9]+");
IList <int> ids = rx.Matches(inputs[1]).Select(m => int.Parse(m.Value)).ToList();
int minId = -1;
int minWait = -1;
foreach (int id in ids)
{
int intervalWait = id - (arriveTime % id);
if (intervalWait < minWait || minWait < 0)
{
minWait = intervalWait;
minId = id;
}
}
return(minId * minWait);
}
public static long Part2()
{
const string path = Helpers.inputPath + @"\day13\input.txt";
IList <string> inputs = Helpers.GetFileAsLines(path);
Regex rx = new Regex("[0-9]+|x");
IList <int> ids = rx.Matches(inputs[1]).Select(m => {
if (m.Value.Equals("x"))
{
return(1);
}
else
{
return(int.Parse(m.Value));
}
}).ToList();
int largestIndex = ids.IndexOf(ids.Max());
long t = -largestIndex;
long multipleToAdd = ids[largestIndex];
while (t <= 0)
{
t += multipleToAdd;
}
long tDebug = 0;
IList <int> idIndices = ids
.Select((id, index) => { if (id > 1)
{
return(index);
}
else
{
return(-1);
} })
.Where(i => i >= 0)
.ToList();
// whether this index is considered in the multipleToAdd variable
IDictionary <int, bool> lockedIn = new Dictionary <int, bool>();
foreach (int i in idIndices)
{
lockedIn.Add(i, false);
}
lockedIn[largestIndex] = true;
while (true)
{
foreach (int i in idIndices)
{
if ((t + i) % ids[i] == 0 && !lockedIn[i])
{
// MULTIPLY THE NUMBER TO ADD BY ids[i] ONCE ids[i] WORKS WITH THE CURRENT t VALUE
multipleToAdd *= ids[i];
lockedIn[i] = true;
if (lockedIn.Values.Aggregate(true, (acc, val) => acc & val))
{
return(t);
}
}
}
t += multipleToAdd;
}
}
