pub enum Product {
    Number(i32),
    Product(Box<Product>, Box<Product>),
}

impl Product {
    pub fn sign(&self) -> i32 {
        match self {
            Product::Number(n) => n.signum(),
            Product::Product(p1, p2) => {
                let s1 = p1.sign();
                if s1 == 1 {
                    p2.sign()
                } else {
                    -p2.sign()
                }
            }
        }
    }
}



struct ChainedProduct {
    value: i32,
    next: Option<Box<ChainedProduct>>,
}


impl ChainedProduct {
    pub fn new(values: &[i32]) -> ChainedProduct {
        assert!(!values.is_empty());
        ChainedProduct {
            value: values[0],
            next: if values.len() > 1 {
                Some(Box::new(ChainedProduct::new(&values[1..])))
            } else {
                None
            },
        }
    }
    pub fn sign(self) -> i32 {
        if self.next.is_none() {
            return self.value.signum();
        }
        if self.value.signum() == 1 {
            self.next.unwrap().sign()
        } else {
            -self.next.unwrap().sign()
        }
    }
}

fn main() {
    let p = Product::new(-1, Product::new(2, Product::new(-3, Product::new(1, Product::new(-2, Product::new(-3, -4))))));
    println!("{}", p.sign());
    let cp = ChainedProduct::new(&[-1, 2, -3, 1, -2, -3, -4]);
    println!("{}", cp.sign());
}