/* The alg creates possible values from known 4 digits (1,3,7,9) instead of standard loop from 1 to n Also it tests only smallest values from the given set. For example, if 113 is found, there's no need to check 131 and 311 as they are already found. SoloLearn time limit does not allow finding anything greater than 15 digits. However, you can do that on your own PC. 19 digit number will be found in a few minutes. */ #include #include using namespace std; bool isPrime(uint64_t x) { if (x<2) return false; if (x<=3) return true; if ((x & 1)==0) return false; if ((x % 3)==0) return false; for (uint64_t t = 5;; t+=6) { uint64_t tt = t*t; if (tt>x) return true; if (tt v) { a*=10; if (v.size()==1) { cout << (a+v[0]) << endl; } else { for (int i = 0; i< v.size(); i++) { if (i && v[i] == v[i-1]) continue; vector v2 = v; v2.erase(v2.begin()+i); iterationPrint(a+v[i], v2); }; } } void printPermute(uint64_t a) { vector v; while (a>0) { //v.push_back(a%10); v.insert(v.begin(), a%10); a/=10; } iterationPrint(0, v); } bool iterationPermute (uint64_t a, vector v) { a*=10; if (v.size()==1) { return isPrime(a+v[0]); } else for (int i = 0; i< v.size(); i++) { if (i && v[i] == v[i-1]) continue; vector v2 = v; v2.erase(v2.begin()+i); if (!iterationPermute(a+v[i], v2)) return false; }; return true; } void testPermute(uint64_t a) { vector v; uint64_t _a = a; while (_a>0) { v.push_back(_a%10); _a/=10; } if( iterationPermute(0, v)) { printPermute(a); } } void test(uint64_t a) { if (isPrime(a)) testPermute(a); } void iteration (uint64_t a, int* d, int size, int level) { a*=10; for (int i = 0; i

Permutable Primes (optimized)