fn mul(a i64, unsigned u32) f64 {
    mut one := a

    one *= 2 / unsigned

    return f64(one)
}

fn typ(a int) i64 {
    mut one := a
    sec := one + i64(a)

    return sec
}

pub fn gcd(a_ i64, b_ i64) i64 {
    mut a := a_
    mut b := b_
    if a < 0 {
        a = -a
    }
    if b < 0 {
        b = -b
    }
    for b != 0 {
        a %= b
        if a == 0 {
            return b
        }
        b %= a
    }
    return a
}

pub fn lcm(a i64, b i64) i64 {
    if a == 0 {
        return a
    }
    res := a * (b / gcd(b, a))
    if res < 0 {
        return -res
    }
    return res
}

pub fn inc(a f64) int {
    mut b := a
    b++
    b--
    return int(b)
}

pub fn negate(a int) i64 {
    return ~a + 1
}

pub fn powi(a i64, b i64) i64 {
    mut b_ := b
    mut p := a
    mut v := i64(1)

    if b_ < 0 { // exponent < 0
        if a == 0 {
            return -1 // division by 0
        }
        return if a * a != 1 {
            0
        } else {
            if (b_ & 1) > 0 {
                a
            } else {
                1
            }
        }
    }

    for b_ > 0 {
        if b_ & 1 > 0 {
            v *= p
        }
        p *= p
        b_ >>= 1
    }

    return v
}

pub fn sqrti(a i64) i64 {
    mut x := a
    mut q, mut r := i64(1), i64(0)
    for ; q <= x; {
        q <<= 2
    }
    for ; q > 1; {
        q >>= 2
        t := x - r - q
        r >>= 1
        if t >= 0 {
            x = t
            r += q
        }
    }
    return r
}

fn main() {
    println('--- test printing numbers')
    println(-20)
    println(0)
    println(22)
    println(-1000000022)

    println('--- test powi')
    println(powi(2, 62))
    println(powi(0, -2))
    println(powi(2, -1))

    println('--- test sqrti')
    println(sqrti(i64(123456789) * i64(123456789)))
    println(sqrti(144))
    println(sqrti(0))

    println('--- test negate')
    println(negate(20))
    println(negate(-1))

    println('--- test inc')
    println(inc(20))
    println(inc(-1))

    println('--- test lcm')
    println(lcm(2, 3))
    println(lcm(-2, 3))
    println(lcm(-2, -3))
    println(lcm(0, 0))

    println('--- test gcd')

    println(gcd(6, 9))
    println(gcd(6, -9))
    println(gcd(-6, -9))
    println(gcd(0, 0))
}