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feat(*): Add 2021-09 files (part 1 working, part 2 not)

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Josh Creek
2021-12-09 17:26:21 +00:00
parent 2e70f9e457
commit c16b1f3fc2
5 changed files with 312 additions and 0 deletions
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2021/09/Program.cs
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using Creek.HelpfulExtensions;
namespace Day09
{
class Program
{
public static int arraySizeX;
public static int arraySizeY;
static void Main(string[] args)
{
string[] lines = File.ReadAllLines("input.txt");
//Part1(lines);
Part2(lines);
}
static void Part1(string[] lines)
{
arraySizeX = lines[0].Length;
arraySizeY = lines.Count();
int[,] array = new int[arraySizeX, arraySizeY];
foreach (var (line, index) in lines.WithIndex())
{
for (int i = 0; i < line.Length; i++)
{
array[i,index] = int.Parse(line[i].ToString());
}
}
List<int> lowPoints = new List<int>();
// Check each number in the array
for (int i = 0; i < arraySizeX; i++)
{
for (int j = 0; j < arraySizeY; j++)
{
if (IsLowPoint(array, i, j))
{
lowPoints.Add(array[i,j]);
}
}
}
// Risk level of a low point is 1 plus height
int totalRiskLevel = lowPoints.Sum() + lowPoints.Count();
Console.WriteLine($"Total Risk Level: {totalRiskLevel}");
}
static void Part2(string[] lines)
{
arraySizeX = lines[0].Length;
arraySizeY = lines.Count();
int[,] array = new int[arraySizeX, arraySizeY];
foreach (var (line, index) in lines.WithIndex())
{
for (int i = 0; i < line.Length; i++)
{
array[i, index] = int.Parse(line[i].ToString());
}
}
List<(int x, int y)> lowPointLocations = new List<(int x, int y)>();
// Check each number in the array
for (int i = 0; i < arraySizeX; i++)
{
for (int j = 0; j < arraySizeY; j++)
{
if (IsLowPoint(array, i, j))
{
lowPointLocations.Add((i, j));
}
}
}
// There is a basin for every low point, bounded by 9s and the edge of the array
// Find these basins, along with the count of how many locations are in each basin
List<int> basinLocationCount = new List<int>();
foreach ((int x, int y) location in lowPointLocations)
{
// For each low point, find all the locations within its basin
Console.WriteLine("Starting new basin");
List<(int x, int y)> locationsInBasin = new List<(int x, int y)>();
FindBasinLocations(array, ref locationsInBasin, location);
basinLocationCount.Add(locationsInBasin.Count());
}
Console.WriteLine($"Total Basin Locations: {basinLocationCount.Count()}");
}
static void FindBasinLocations(int[,] array, ref List<(int x, int y)> locationsInBasin, (int x, int y) location)
{
List<(int x, int y)> relativeLocations = new List<(int x, int y)>()
{
//(location.x - 1, location.y - 1),
//(location.x, location.y - 1),
//(location.x + 1, location.y - 1),
//(location.x - 1, location.y),
//(location.x + 1, location.y),
//(location.x - 1, location.y + 1),
//(location.x, location.y + 1),
//(location.x + 1, location.y + 1),
};
try
{
relativeLocations.Add((location.x - 1, location.y - 1));
relativeLocations.Add((location.x, location.y - 1));
relativeLocations.Add((location.x + 1, location.y - 1));
relativeLocations.Add((location.x - 1, location.y));
relativeLocations.Add((location.x + 1, location.y));
relativeLocations.Add((location.x - 1, location.y + 1));
relativeLocations.Add((location.x, location.y + 1));
relativeLocations.Add((location.x + 1, location.y + 1));
}
catch (Exception ex)
{
Console.WriteLine($"{location.x},{location.y} errored");
}
// For every direction, if there's a 9 or no element stop, otherwise, go again from that location, excluding locations we've already considered
foreach ((int x, int y) relativeLocation in relativeLocations)
{
int newX = location.x + relativeLocation.x;
int newY = location.y + relativeLocation.y;
bool condition1 = IsNotHighPointOrOutOfArray(array, newX, newY);
bool condition2 = condition1 ? array[newX, newY] < 9 : false;
bool condition3 = condition1 ? !locationsInBasin.Contains((newX, newY)) : false;
//Console.WriteLine($"{condition1} - {condition2} - {condition3}");
if (condition1 && condition2 && condition3)
{
locationsInBasin.Add((newX, newY));
Console.WriteLine($"{newX},{newY} added with value {array[newX, newY]}");
FindBasinLocations(array, ref locationsInBasin, relativeLocation);
}
}
}
static bool IsNotHighPointOrOutOfArray(int[,] array, int x, int y)
{
if (IsInArray(x, y) && array[x, y] < 9)
{
return true;
}
else
{
return false;
}
}
static bool IsLowPoint(int[,] array, int x, int y)
{
// top left x-1, y-1
// top middle x, y-1
// top right x+1, y-1
// left x-1, y
// right x+1, y
// bottom left x-1, y+1
// bottom middle x, y+1
// bottom right x+1, y+1
// Compare all EXISTING positions around the current position and if any of them are lowest than the value in the current position return false
int currentPosition = array[x, y];
if (IsInArray(x-1, y-1) && array[x-1, y-1] < currentPosition)
{
return false;
}
else if (IsInArray(x, y - 1) && array[x, y - 1] < currentPosition)
{
return false;
}
else if (IsInArray(x + 1, y - 1) && array[x + 1, y - 1] < currentPosition)
{
return false;
}
else if (IsInArray(x - 1, y) && array[x - 1, y] < currentPosition)
{
return false;
}
else if (IsInArray(x + 1, y) && array[x + 1, y] < currentPosition)
{
return false;
}
else if (IsInArray(x - 1, y + 1) && array[x - 1, y + 1] < currentPosition)
{
return false;
}
else if (IsInArray(x, y + 1) && array[x, y + 1] < currentPosition)
{
return false;
}
else if (IsInArray(x + 1, y + 1) && array[x + 1, y + 1] < currentPosition)
{
return false;
}
else
{
Console.WriteLine($"{x},{y}: {currentPosition}");
return true;
}
}
static bool IsInArray(int x, int y)
{
if (x >= 0 && x < arraySizeX && y >= 0 && y < arraySizeY)
{
return true;
}
else
{
return false;
}
}
}
}