Ext euclid C++ 1 2 3 4 5 6 7 8 9// ax + by = gcd(a, b) を満たす (x, y) std::pair<long long, long long> ext_euclid(long long a, long long b) { if (b == 0) return make_pair(1, 0); long long x, y; tie(y, x) = ext_euclid(b, a % b); y -= a / b * x; return make_pair(x, y); }}