protected override void SolvePartTwo()
{
var centerGrid = new ErisGrid(sanitizedInput, true);
centerGrid.DoTimeSteps(200);
resultPartTwo = centerGrid.CountAllBugs(true).ToString();
}
public void Step()
{
if (isRecursiveGrid)
{
//add grids to current outers
var currentOuter = FindOutermostGrid();
var currentInner = FindInnermostGrid();
var newOuter = new ErisGrid(currentOuter, false);
currentOuter.gridOutsideThis = newOuter;
var newInner = new ErisGrid(currentInner, true);
currentInner.gridInsideThis = newInner;
//determine which indices to update for every grid
var bitsToFlipPerGrid = new List <(ErisGrid, IEnumerable <int>)>();
var currentGrid = newOuter;
while (currentGrid != null)
{
bitsToFlipPerGrid.Add((currentGrid, currentGrid.DetermineWhichBitsToFlip()));
currentGrid = currentGrid.gridInsideThis;
}
//update indices where necessary
foreach (var(grid, indices) in bitsToFlipPerGrid)
{
foreach (var index in indices)
{
grid.state[index] = !grid.state[index];
}
}
//delete empty grids on the edges
currentGrid = newOuter;
while (currentGrid != null && currentGrid.GetBiodiversity() == 0)
{
currentGrid = currentGrid.gridInsideThis;
if (currentGrid != null)
{
currentGrid.gridOutsideThis.gridInsideThis = null;
currentGrid.gridOutsideThis = null;
}
}
currentGrid = newInner;
while (currentGrid != null && currentGrid.GetBiodiversity() == 0)
{
currentGrid = currentGrid.gridOutsideThis;
if (currentGrid != null)
{
currentGrid.gridInsideThis.gridOutsideThis = null;
currentGrid.gridInsideThis = null;
}
}
}
else
{
foreach (var index in DetermineWhichBitsToFlip())
{
state[index] = !state[index];
}
}
}
public ErisGrid(ErisGrid other, bool thisInsideOther) : this(true)
{
if (thisInsideOther)
{
gridOutsideThis = other;
}
else
{
gridInsideThis = other;
}
}
public int GetFirstRepeatedBiodiversity()
{
var grid = new ErisGrid(sanitizedInput, false);
var observedBiodiversities = new HashSet <int>()
{
grid.GetBiodiversity()
};
while (true)
{
grid.Step();
var biodiversity = grid.GetBiodiversity();
if (observedBiodiversities.Contains(biodiversity))
{
return(biodiversity);
}
observedBiodiversities.Add(biodiversity);
}
}
