public static int Magnitude(ISnailfishNumber num)
{
if (num is SnailfishValue value)
{
return(value.Value);
}
if (num is SnailfishPair pair)
{
return(3 * Magnitude(pair.X) + 2 * Magnitude(pair.Y));
}
throw new NotImplementedException();
}
public static bool Split(ISnailfishNumber num)
{
if (num is SnailfishValue)
{
return(false);
}
Stack <(ISnailfishNumber number, SnailfishPair?parent)> stack = new();
stack.Push((num, null));
while (stack.Count > 0)
{
(var curr, var parent) = stack.Pop();
if (curr is SnailfishValue value)
{
if (value.Value >= 10)
{
int x = value.Value / 2;
int y = value.Value / 2 + value.Value % 2;
var newValue = new SnailfishPair(x, y);
if (parent?.X == curr)
{
parent.X = newValue;
}
else if (parent?.Y == curr)
{
parent.Y = newValue;
}
return(true);
}
}
else if (curr is SnailfishPair pair)
{
stack.Push((pair.Y, pair));
stack.Push((pair.X, pair));
}
}
return(false);
}
public static bool Explode(ISnailfishNumber num)
{
if (num is SnailfishValue)
{
return(false);
}
Stack <(int level, ISnailfishNumber number, SnailfishPair?parent)> stack = new();
stack.Push((1, num, null));
SnailfishValue?lastValue = null;
int? toMoveRight = null;
while (stack.Count > 0)
{
(int level, var curr, var parent) = stack.Pop();
if (curr is SnailfishPair pair)
{
if (toMoveRight == null && level > 4 && pair.X is SnailfishValue x && pair.Y is SnailfishValue y)
{
if (lastValue != null)
{
lastValue.Value += x.Value;
}
toMoveRight = y.Value;
if (parent?.X == curr)
{
parent.X = new SnailfishValue(0);
}
else if (parent?.Y == curr)
{
parent.Y = new SnailfishValue(0);
}
}
else
{
stack.Push((level + 1, pair.Y, pair));
stack.Push((level + 1, pair.X, pair));
}
}
public static void Reduce(ISnailfishNumber num)
{
while (Explode(num) || Split(num))
{
}
}
