internal FactorCollection Copy()
{
FactorCollection result = new FactorCollection();
result.AddRange(this.Select(factor => new Factor {
Prime = factor.Prime, Cardinality = factor.Cardinality
}));
return(result);
}
public static FactorCollection Factorize(this long number)
{
long initNumber = number;
if (FactorCollections.ContainsKey(initNumber))
{
return(FactorCollections[initNumber]);
}
FactorCollection results = new FactorCollection();
int sqrt = (int)Math.Sqrt(number);
for (int i = 0; i < PrimeManager.Primes.Count; i++)
{
if (number == 1)
{
break;
}
if (PrimeManager.Primes[i] > sqrt)
{
results.Add(new Factor {
Prime = number, Cardinality = 1
});
number = 1;
break;
}
if (number % PrimeManager.Primes[i] == 0)
{
results.Add(new Factor {
Prime = PrimeManager.Primes[i], Cardinality = 1
});
number /= PrimeManager.Primes[i];
}
if (FactorCollections.ContainsKey(number))
{
results = results.Append(FactorCollections[number]);
FactorCollections.Add(initNumber, results);
return(results);
}
while (number % PrimeManager.Primes[i] == 0)
{
results[results.Count - 1].Cardinality++;
number /= PrimeManager.Primes[i];
}
}
if (number != 1)
{
results.Add(new Factor {
Prime = number, Cardinality = 1
});
}
FactorCollections.Add(initNumber, results);
return(results);
}
internal FactorCollection Square()
{
FactorCollection result = this.Copy();
foreach (Factor factor in result)
{
factor.Cardinality *= 2;
}
return(result);
}
internal FactorCollection Append(FactorCollection that)
{
//assumes well ordering by primes
FactorCollection result = new FactorCollection();
int tindex = 0;
int findex = 0;
while ((findex < that.Count) && (tindex < this.Count))
{
if (this[tindex].Prime < that[findex].Prime)
{
result.Add(new Factor {
Prime = this[tindex].Prime, Cardinality = this[tindex].Cardinality
});
tindex++;
}
else if (this[tindex].Prime > that[findex].Prime)
{
result.Add(new Factor {
Prime = that[findex].Prime, Cardinality = that[findex].Cardinality
});
findex++;
}
else
{
result.Add(new Factor
{
Prime = this[tindex].Prime,
Cardinality = this[tindex].Cardinality + that[findex].Cardinality
});
tindex++;
findex++;
}
}
for (; tindex < this.Count; tindex++)
{
result.Add(new Factor {
Prime = this[tindex].Prime, Cardinality = this[tindex].Cardinality
});
}
for (; findex < that.Count; findex++)
{
result.Add(new Factor {
Prime = that[findex].Prime, Cardinality = that[findex].Cardinality
});
}
return(result);
}
internal FactorCollection Combine(FactorCollection that)
{
FactorCollection result = new FactorCollection();
int tindex = 0;
int findex = 0;
while ((findex < that.Count) && (tindex < this.Count))
{
if (this[tindex].Prime < that[findex].Prime)
{
result.Add(new Factor {
Prime = this[tindex].Prime, Cardinality = this[tindex].Cardinality
});
tindex++;
}
else if (this[tindex].Prime > that[findex].Prime)
{
result.Add(new Factor {
Prime = that[findex].Prime, Cardinality = that[findex].Cardinality
});
findex++;
}
else
{
result.Add(new Factor
{
Prime = this[tindex].Prime,
Cardinality = Math.Max(this[tindex].Cardinality, that[findex].Cardinality)
});
tindex++;
findex++;
}
}
for (; tindex < this.Count; tindex++)
{
result.Add(new Factor {
Prime = this[tindex].Prime, Cardinality = this[tindex].Cardinality
});
}
for (; findex < that.Count; findex++)
{
result.Add(new Factor {
Prime = that[findex].Prime, Cardinality = that[findex].Cardinality
});
}
return(result);
}
public bool Equals(FactorCollection other)
{
if (other.Count != Count)
{
return(false);
}
foreach (Factor factor in this)
{
if (!other.Contains(factor))
{
return(false);
}
}
return(true);
}