Plus Minus (https://www.hackerrank.com/challenges/plus-minus/problem)

main.rs

use std::io;

fn main() {

    let (l, arr) = get_input();
    let (p, n, z) = plus_minus(&arr);

    println!(
        "{:.6}\n{:.6}\n{:.6}", 
        avg(p as f32, l as f32), 
        avg(n as f32, l as f32), 
        avg(z as f32, l as f32)
    );
}

fn get_input () -> (usize, Vec<i32>) {
    let mut s = String::new();
    io::stdin()
        .read_line(&mut s)
        .expect("Failed to read line");

    let n = s.trim()
        .parse::<usize>()
        .expect("Invalid input");

    s.clear();
    io::stdin()
        .read_line(&mut s)
        .expect("Failed to read line");
    
    let mut arr = vec![0; n];
    for (i, value) in s.trim().split_whitespace().enumerate() {
        if i > n {
            break;
        }
        arr[i] = value.parse::<i32>().unwrap_or(0);
    }

    (n, arr)
}

fn avg(x :f32, y :f32) -> f32 {
    if y == 0.0 {
        0.0
    } else {
        x / y
    }
}

fn plus_minus(arr: &[i32]) -> (i32, i32, i32) {
    let mut p = 0;
    let mut n = 0;
    let mut z = 0;

    for i in arr.iter() {
        if *i > 0 {
            p += 1;
        } else if *i < 0 {
            n += 1;
        } else {
            z += 1;
        }
    }

    (p, n, z)
}

#[test]
fn test_plus_minus() {
    let (x, y, z) = plus_minus(&[1,1,1,0,-1,-1]);
    assert_eq!(3, x);
    assert_eq!(2, y);
    assert_eq!(1, z);
}

#[test]
fn test_avg() {
    assert_eq!(2.0, avg(10.0, 5.0));
    assert_eq!(3.0, avg(9.0, 3.0));
    assert_eq!(4.0, avg(16.0, 4.0));
}