diff options
Diffstat (limited to 'math/millerRabin.cpp')
| -rw-r--r-- | math/millerRabin.cpp | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/math/millerRabin.cpp b/math/millerRabin.cpp new file mode 100644 index 0000000..d41f33a --- /dev/null +++ b/math/millerRabin.cpp @@ -0,0 +1,19 @@ +// Theoretisch: n < 318,665,857,834,031,151,167,461 (> 10^23) +// Praktisch: n <= 10^18 (long long) +// Laufzeit: O(log n) +bool isPrime(ll n) { + if(n == 2) return true; + if(n < 2 || n % 2 == 0) return false; + ll d=n-1,j=0; + while(d % 2 == 0) d >>= 1, j++; + for(int a = 2; a <= min((ll)37, n-1); a++) { + ll v = pow_mod(a, d, n); + if(v == 1 || v == n-1) continue; + for(int i = 1; i <= j; i++) { + v = mult_mod(v, v, n); + if(v == n-1 || v <= 1) break; + } + if(v != n-1) return false; + } + return true; +} |
