Initial data commit

Task/Farey-sequence/Rust/farey-sequence.rust

@@ -0,0 +1,56 @@
+#[derive(Copy, Clone)]
+struct Fraction {
+    numerator: u32,
+    denominator: u32,
+}
+
+use std::fmt;
+
+impl fmt::Display for Fraction {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "{}/{}", self.numerator, self.denominator)
+    }
+}
+
+impl Fraction {
+    fn new(n: u32, d: u32) -> Fraction {
+        Fraction {
+            numerator: n,
+            denominator: d,
+        }
+    }
+}
+
+fn farey_sequence(n: u32) -> impl std::iter::Iterator<Item = Fraction> {
+    let mut a = 0;
+    let mut b = 1;
+    let mut c = 1;
+    let mut d = n;
+    std::iter::from_fn(move || {
+        if a > n {
+            return None;
+        }
+        let result = Fraction::new(a, b);
+        let k = (n + b) / d;
+        let next_c = k * c - a;
+        let next_d = k * d - b;
+        a = c;
+        b = d;
+        c = next_c;
+        d = next_d;
+        Some(result)
+    })
+}
+
+fn main() {
+    for n in 1..=11 {
+        print!("{}:", n);
+        for f in farey_sequence(n) {
+            print!(" {}", f);
+        }
+        println!();
+    }
+    for n in (100..=1000).step_by(100) {
+        println!("{}: {}", n, farey_sequence(n).count());
+    }
+}