#[derive(Debug)]
struct Up {
    weight: f64,
    cap: usize,
    conns: usize,
}

fn main() {
    let mut ups = [
        Up {
            weight: 0.9,
            cap: 300,
            conns: 0,
        },
        Up {
            weight: 0.1,
            cap: 300,
            conns: 0,
        },
    ];

    for i in 0..100 {
        let r: Option<usize> = {
            use std::cmp::Ordering::Equal;
            let r = ups
                .iter()
                .enumerate()
                .filter(|(i, e)| e.conns < e.cap)
                .min_by(|(i, a), (j, b)| {
                    let a = a.conns as f64 / a.weight;
                    let b = b.conns as f64 / b.weight;
                    a.partial_cmp(&b).unwrap_or(Equal)
                })
                .map(|(i, ..)| i);
            r
        };

        if let Some(idx) = r {
            ups[idx].conns += 1;
        }
        let arr = [
            ups[0].conns,
            ups[1].conns,
        ];
        println!("ups: {:?}", arr);
    }
}