// ax - by = k // by - ax = k use std::io::Write; fn run() { input! { t: usize, ask: [(u64, u64, u64, u64); t], } let calc = |m: u64, a: u64, b: u64, k: u64| -> u64 { let g = binary_gcd(a, b); let m = m / g; let a = a / g; let b = b / g; if k % g != 0 { return 0; } let k = k / g; let lcm = a * b; let mut ans = 0; if k == a { ans += m / lcm * (b - a + 1) - 1; let m = m % lcm; let x = m / a; let y = m / b; ans += x - y; } else if k < a { ans += m / lcm * 2; let p = inv(((a * b - b) % a) as i64, a as i64) as u64; let y = k * p % a; let x = (k + b * y) / a; if a * x <= m % lcm { ans += 1; } let p = inv((b % a) as i64, a as i64) as u64; let y = k * p % a; if b * y <= m % lcm { ans += 1; } } ans }; let out = std::io::stdout(); let mut out = std::io::BufWriter::new(out.lock()); for (m, a, b, k) in ask { writeln!(out, "{}", calc(m, a, b, k)).ok(); } } fn main() { run(); } // a * x = 1 (mod m) pub fn inv(a: i64, m: i64) -> i64 { if a == 1 { 1 } else { m + (-m * inv(m % a, a) + 1) / a } } // ---------- begin binary_gcd ---------- pub fn binary_gcd(a: u64, b: u64) -> u64 { if a == 0 || b == 0 { return a + b; } let x = a.trailing_zeros(); let y = b.trailing_zeros(); let mut a = a >> x; let mut b = b >> y; while a != b { let x = (a ^ b).trailing_zeros(); if a < b { std::mem::swap(&mut a, &mut b); } a = (a - b) >> x; } a << x.min(y) } // ---------- end binary_gcd ---------- // ---------- begin input macro ---------- // reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 #[macro_export] macro_rules! input { (source = $s:expr, $($r:tt)*) => { let mut iter = $s.split_whitespace(); input_inner!{iter, $($r)*} }; ($($r:tt)*) => { let s = { use std::io::Read; let mut s = String::new(); std::io::stdin().read_to_string(&mut s).unwrap(); s }; let mut iter = s.split_whitespace(); input_inner!{iter, $($r)*} }; } #[macro_export] macro_rules! input_inner { ($iter:expr) => {}; ($iter:expr, ) => {}; ($iter:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($iter, $t); input_inner!{$iter $($r)*} }; } #[macro_export] macro_rules! read_value { ($iter:expr, ( $($t:tt),* )) => { ( $(read_value!($iter, $t)),* ) }; ($iter:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($iter, $t)).collect::>() }; ($iter:expr, chars) => { read_value!($iter, String).chars().collect::>() }; ($iter:expr, bytes) => { read_value!($iter, String).bytes().collect::>() }; ($iter:expr, usize1) => { read_value!($iter, usize) - 1 }; ($iter:expr, $t:ty) => { $iter.next().unwrap().parse::<$t>().expect("Parse error") }; } // ---------- end input macro ----------