106 lines
1.8 KiB
C++
106 lines
1.8 KiB
C++
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#include <algebra/algebra.h>
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unsigned
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unsigned_gcd (unsigned a, unsigned b)
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{
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while (b != 0)
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{
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unsigned t = a % b;
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a = b;
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b = t;
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}
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return a;
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}
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unsigned
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int_gcd (int a, int b)
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{
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return unsigned_gcd ((unsigned)std::abs (a),
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(unsigned)std::abs (b));
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}
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uint64
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uint64_gcd (uint64 a, uint64 b)
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{
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while (b != 0)
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{
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uint64 t = a % b;
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a = b;
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b = t;
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}
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return a;
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}
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uint64
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int64_gcd (int64 a, int64 b)
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{
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return uint64_gcd ((uint64)std::abs (a),
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(uint64)std::abs (b));
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}
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static triple<unsigned, int, int>
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extended_gcd_1 (unsigned a, unsigned b)
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{
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if (b == 0)
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return triple<unsigned, int, int> (a, 1, 0);
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unsigned t = a % b;
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if (!t)
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return triple<unsigned, int, int> (b, 0, 1);
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else
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{
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triple<unsigned, int, int> s = extended_gcd (b, t);
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unsigned d = s.first;
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int x = s.third,
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y = s.second - s.third * (a / b);
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assert ((int)d == (int)a*x + (int)b*y);
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return triple<unsigned, int, int> (d, x, y);
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}
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}
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triple<unsigned, int, int>
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extended_gcd (int a, int b)
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{
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triple<unsigned, int, int> t = extended_gcd_1 (std::abs (a),
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std::abs (b));
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unsigned d = t.first;
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int x = t.second,
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y = t.third;
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if (a < 0)
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x *= -1;
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if (b < 0)
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y *= -1;
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assert ((int)d == a*x + b*y);
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return triple<unsigned, int, int> (d, x, y);
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}
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unsigned
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unsigned_lcm (unsigned a, unsigned b)
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{
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return (a / unsigned_gcd (a, b)) * b;
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}
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uint64
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uint64_lcm (uint64 a, uint64 b)
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{
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return (a / uint64_gcd (a, b)) * b;
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}
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unsigned int_lcm (int a, int b)
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{
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return unsigned_lcm ((unsigned)std::abs (a),
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(unsigned)std::abs (b));
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}
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uint64 int64_lcm (int64 a, int64 b)
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{
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return uint64_lcm ((uint64)std::abs (a),
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(uint64)std::abs (b));
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}
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