Initial data commit

Task/Yellowstone-sequence/Rust/yellowstone-sequence.rust

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+// [dependencies]
+// num = "0.3"
+// plotters = "^0.2.15"
+
+use num::integer::gcd;
+use plotters::prelude::*;
+use std::collections::HashSet;
+
+fn yellowstone_sequence() -> impl std::iter::Iterator<Item = u32> {
+    let mut sequence: HashSet<u32> = HashSet::new();
+    let mut min = 1;
+    let mut n = 0;
+    let mut n1 = 0;
+    let mut n2 = 0;
+    std::iter::from_fn(move || {
+        n2 = n1;
+        n1 = n;
+        if n < 3 {
+            n += 1;
+        } else {
+            n = min;
+            while !(!sequence.contains(&n) && gcd(n1, n) == 1 && gcd(n2, n) > 1) {
+                n += 1;
+            }
+        }
+        sequence.insert(n);
+        while sequence.contains(&min) {
+            sequence.remove(&min);
+            min += 1;
+        }
+        Some(n)
+    })
+}
+
+// Based on the example in the "Quick Start" section of the README file for
+// the plotters library.
+fn plot_yellowstone(filename: &str) -> Result<(), Box<dyn std::error::Error>> {
+    let root = BitMapBackend::new(filename, (800, 600)).into_drawing_area();
+    root.fill(&WHITE)?;
+    let mut chart = ChartBuilder::on(&root)
+        .caption("Yellowstone Sequence", ("sans-serif", 24).into_font())
+        .margin(10)
+        .x_label_area_size(20)
+        .y_label_area_size(20)
+        .build_ranged(0usize..100usize, 0u32..180u32)?;
+    chart.configure_mesh().draw()?;
+    chart.draw_series(LineSeries::new(
+        yellowstone_sequence().take(100).enumerate(),
+        &BLUE,
+    ))?;
+    Ok(())
+}
+
+fn main() {
+    println!("First 30 Yellowstone numbers:");
+    for y in yellowstone_sequence().take(30) {
+        print!("{} ", y);
+    }
+    println!();
+    match plot_yellowstone("yellowstone.png") {
+        Ok(()) => {}
+        Err(error) => eprintln!("Error: {}", error),
+    }
+}