Educational Codeforces Round (rated for Div. 2) B. Weird subtraction process[number theory/Euclidean algorithm]

Https://zh.wikipedia.org/wiki/%E8%BC%BE%E8%BD%89%E7%9B%B8%E9%99%A4%E6%B3%95

The same is true of the model, when it is reduced several times.

In Euclid's initial description, the quotient and remainder are computed by successive subtraction, that is, the R K −1 is subtracted from the Rk −2 until it is less than Rk− 1. A more efficient approach is to use integer division and modulo to compute quotient and remainder:

R k ≡ r k−2 mod r k−1

subtraction version defined in Euclid , the take remainder operation is subtracted and replaced

Educational Codeforces Round (rated for Div. 2) B. Weird subtraction process[number theory/Euclidean algorithm]