public String factors(int lst)
{
PrimeNumbersFactors pnf = new PrimeNumbersFactors();
Dictionary <long, long> pfactors = pnf.PollardRhoPrimeFactors((long)lst);
string res = "";
if (pfactors.Count == 0)
{
res = $"({lst})";
}
else
{
foreach (var f in pfactors.OrderBy(x => x.Key))
{
if (f.Value == 1)
{
res += $"({f.Key})";
}
else
{
res += $"({f.Key}**{f.Value})";
}
}
}
return(res);
}
public long[] CountKprimes(int k, long start, long end)
{
List <long> kprimes = new List <long>();
PrimeNumbersFactors pnf = new PrimeNumbersFactors();
PrimeNumbersCheck pchk = new PrimeNumbersCheck();
if (k > 1)
{
if (start < (1 << k))
{
start = (1 << k);
}
for (long i = start; i <= end; i++)
{
Dictionary <long, long> factors = pnf.PollardRhoPrimeFactors(i);
if (factors.Sum(x => x.Value) == k)
{
kprimes.Add(i);
}
}
}
else
{
if (start < 2)
{
start = 2;
}
for (long i = start; i <= end; i++)
{
if (pchk.IsPrimeMRTest(i))
{
kprimes.Add(i);
}
}
}
return(kprimes.ToArray());
}
public int Puzzle(int s)
{
Console.WriteLine($"s = {s}");
if (s < 138)
{
return(0);
}
int res = 0;
Stopwatch sw = Stopwatch.StartNew();
List <long> p1 = new List <long>();
List <long> p3 = new List <long>();
List <long> p7 = new List <long>();
PrimeNumbersFactors pnf = new PrimeNumbersFactors();
BitArray dotest = new BitArray(s - 10 + 1, true);
//maksymalna liczba jest s - 8 - 2 = s - 10, minimalna 2
//wygenerowane listy sa zawsze posortowane
for (long i = 2; i <= s - 10; i++)
{
if (!dotest[(int)i])
{
continue;
}
Dictionary <long, long> factors = pnf.PollardRhoPrimeFactors(i);
if (factors.Count == 0)
{
p1.Add(i);
//SetPowersOmmited(dotest, i, 2, 1);
//SetPowersOmmited(dotest, i, 3, 1);
//SetPowersOmmited(dotest, i, 5, 1);
//SetPowersOmmited(dotest, i, 7, 1);
}
else
{
long cnt = factors.Sum(x => x.Value);
if (cnt == 3)
{
p3.Add(i);
}
else if (cnt == 7)
{
p7.Add(i);
}
//if ((cnt == 3) || (cnt == 7))
//{
// //daje ok 25% szybsze generowanie list
// foreach (var item in factors)
// SetPowersOmmited(dotest, i, item.Key, cnt);
//}
}
}
Console.WriteLine($"lists: {sw.ElapsedMilliseconds} ms");
if ((p1.Count == 0) || (p3.Count == 0) || (p7.Count == 0))
{
return(0);
}
Console.WriteLine($"p1={p1.Count}, p3={p3.Count}, p7={p7.Count}");
//bruteforce
//for(int i=0; i<p1.Count; i++)
// for(int j=0; j<p3.Count; j++)
// for(int k=0; k<p7.Count; k++)
// if (p1[i] + p3[j] + p7[k] == s) res++;
//for (int i = 0; i < p1.Count; i++)
// for (int j = 0; j < p3.Count; j++)
// if (p7.BinarySearch(s - (p1[i] + p3[j])) >= 0) res++;
//for (int i = 0; i < p1.Count; i++)
// for (int j = 0; (j < p3.Count) && (p1[i] + p3[j] + p7[0] <= s); j++)
// if (p7.BinarySearch(s - (p1[i] + p3[j])) >= 0) res++;
//z obserwacji wynika ze p7<p1<p3
//for (int i = 0; i < p7.Count; i++)
// for (int j = 0; (j < p1.Count) && (p7[i] + p1[j] + p3[0] <= s); j++)
// if (p3.BinarySearch(s - (p7[i] + p1[j])) >= 0) res++;
//int step = 0;
//for (int i = 0; i < p7.Count; i++)
//{
// Console.WriteLine($"--- step={step}, res={res}");
// int rightboud = p3.Count;
// for (int j = 0; (j < p1.Count) && (p7[i] + p1[j] + p3[0] <= s); j++)
// {
// //int k = p3.BinarySearch(s - (p7[i] + p1[j]));
// int k = p3.BinarySearch(0, rightboud, s - (p7[i] + p1[j]), null);
// if (k >= 0)
// {
// res++;
// Console.WriteLine($"{step}: {i} ({p7[i]}), {j} ({p1[j]}), {k} ({p3[k]}) +++");
// //rightboud = Math.Max(k + 1, p3.Count);
// }
// else
// {
// Console.WriteLine($"{step}: {i} ({p7[i]}), {j} ({p1[j]}), {k} (rightmax={p3[-k]}, expected={s - (p7[i] + p1[j])})");
// rightboud = -k;
// }
// step++;
// }
//}
int step = 0;
for (int i = 0; i < p7.Count; i++)
{
int rightbound = p3.BinarySearch(s - (p7[i] + p1[0]));
if (rightbound < 0)
{
rightbound = -rightbound;
}
else
{
rightbound = Math.Min(rightbound + 1, p3.Count - 1);
}
//Console.WriteLine($"--- step={step}, res={res}, rightbound={rightbound}");
for (int j = 0; (j < p1.Count) && (p7[i] + p1[j] + p3[0] <= s); j++)
{
long sum = p7[i] + p1[j];
long expected = s - sum;
while (rightbound >= 0)
{
if (p3[rightbound] == expected)
{
res++;
//Console.WriteLine($"{step}: {i} ({p7[i]}), {j} ({p1[j]}), {rightbound} ({p3[rightbound]}), res={res}");
break;
}
if (p3[rightbound] < expected)
{
break;
}
rightbound--;
}
//Console.WriteLine($"{step}: {i} ({p7[i]}), {j} ({p1[j]}), expected={expected}, next rb={rightbound}, res={res}");
step++;
}
}
sw.Stop();
Console.WriteLine($"check: {sw.ElapsedMilliseconds} ms");
return(res);
}
