public PlantGeneration EvolveGeneration(PlantGeneration generation)
{
var pots = $"....{generation.PlantPots}....";
//foreach pot (where there are at least 2 pots before it or after it)
//get the pot sequence i-2, i-1, i, i+1, i+2
//lookup the rule
//append the answer to the output
//also need to track the offset...
var builder = new StringBuilder();
for (var i = 2; i < pots.Length - 2; i++)
{
var pot = Enumerable.Range(-2, 5).Aggregate(new StringBuilder(), (sb, x) => sb.Append(pots[i + x])).ToString();
builder.Append(Rules.TryGetValue(pot, out var plant) ? plant : ".");
}
var next = builder.ToString();
var result = new PlantGeneration
{
Offset = generation.Offset,
PlantPots = next
};
result.Offset -= 2;
return(result);
}
public PlantGeneration SolveForGenerations(int generations)
{
var result = new PlantGeneration {
PlantPots = InitialState
};
return(Enumerable.Range(0, generations).Aggregate(result, (current, generation) => EvolveGeneration(current)));
}
public long CountPlants(PlantGeneration generation)
{
return(Enumerable.Range(0, generation.PlantPots.Length)
.Sum(x => generation.PlantPots[x] == '#' ? x + generation.Offset : 0));
}
