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// Copyright © 2026 Mikhail Hogrefe
//
// This file is part of Malachite.
//
// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
use crate::natural::Natural;
use crate::natural_vector::NaturalVector;
use alloc::vec;
use malachite_base::num::arithmetic::traits::{
ModPowerOf2IsReduced, ModPowerOf2Mul, ModPowerOf2MulAssign,
};
use malachite_base::num::basic::traits::{One, Zero};
fn assert_reduced(v: &NaturalVector, c: &Natural, pow: u64) {
assert!(
v.mod_power_of_2_is_reduced(pow),
"self must be reduced mod 2^pow, but {v} has an element >= 2^{pow}"
);
assert!(
c.mod_power_of_2_is_reduced(pow),
"c must be reduced mod 2^pow, but {c} >= 2^{pow}"
);
}
impl ModPowerOf2Mul<Natural> for NaturalVector {
type Output = Self;
/// Multiplies every element of a [`NaturalVector`] by a [`Natural`] modulo $2^k$, taking the
/// vector by value and the scalar by value. The elements and the scalar must already be reduced
/// modulo $2^k$.
///
/// Each product is reduced modulo $2^k$, and the result has the same dimension as the vector.
///
/// $$
/// f(v, c, k) = cv \bmod 2^k.
/// $$
///
/// # Worst-case complexity
/// $T(n, m) = O(nm \log m \log\log m)$
///
/// $M(n, m) = O(m \log m)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is `self.dimension()`, and $m$ is `pow`.
///
/// # Panics
/// Panics if any element of `self`, or `c`, is greater than or equal to $2^k$.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::ModPowerOf2Mul;
/// use malachite_nz::natural::Natural;
/// use malachite_nz::natural_vector::NaturalVector;
///
/// let v = NaturalVector::from_str("(5, 1, 3)").unwrap();
/// assert_eq!(
/// v.mod_power_of_2_mul(Natural::from(3u32), 3).to_string(),
/// "(7, 3, 1)"
/// );
/// ```
#[inline]
fn mod_power_of_2_mul(mut self, c: Natural, pow: u64) -> Self {
self.mod_power_of_2_mul_assign(&c, pow);
self
}
}
impl ModPowerOf2Mul<&Natural> for NaturalVector {
type Output = Self;
/// Multiplies every element of a [`NaturalVector`] by a [`Natural`] modulo $2^k$, taking the
/// vector by value and the scalar by reference. The elements and the scalar must already be
/// reduced modulo $2^k$.
///
/// See the documentation for the [`ModPowerOf2Mul`] implementation that takes the vector and
/// the scalar by value for details.
///
/// # Worst-case complexity
/// $T(n, m) = O(nm \log m \log\log m)$
///
/// $M(n, m) = O(m \log m)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is `self.dimension()`, and $m$ is `pow`.
///
/// # Panics
/// Panics if any element of `self`, or `c`, is greater than or equal to $2^k$.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::ModPowerOf2Mul;
/// use malachite_nz::natural::Natural;
/// use malachite_nz::natural_vector::NaturalVector;
///
/// let v = NaturalVector::from_str("(5, 1, 3)").unwrap();
/// assert_eq!(
/// v.mod_power_of_2_mul(&Natural::from(3u32), 3).to_string(),
/// "(7, 3, 1)"
/// );
/// ```
#[inline]
fn mod_power_of_2_mul(mut self, c: &Natural, pow: u64) -> Self {
self.mod_power_of_2_mul_assign(c, pow);
self
}
}
impl ModPowerOf2Mul<Natural> for &NaturalVector {
type Output = NaturalVector;
/// Multiplies every element of a [`NaturalVector`] by a [`Natural`] modulo $2^k$, taking the
/// vector by reference and the scalar by value. The elements and the scalar must already be
/// reduced modulo $2^k$.
///
/// See the documentation for the [`ModPowerOf2Mul`] implementation that takes the vector and
/// the scalar by value for details.
///
/// # Worst-case complexity
/// $T(n, m) = O(nm \log m \log\log m)$
///
/// $M(n, m) = O(m \log m)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is `self.dimension()`, and $m$ is `pow`.
///
/// # Panics
/// Panics if any element of `self`, or `c`, is greater than or equal to $2^k$.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::ModPowerOf2Mul;
/// use malachite_nz::natural::Natural;
/// use malachite_nz::natural_vector::NaturalVector;
///
/// let v = NaturalVector::from_str("(5, 1, 3)").unwrap();
/// assert_eq!(
/// (&v).mod_power_of_2_mul(Natural::from(3u32), 3).to_string(),
/// "(7, 3, 1)"
/// );
/// ```
#[inline]
fn mod_power_of_2_mul(self, c: Natural, pow: u64) -> NaturalVector {
self.mod_power_of_2_mul(&c, pow)
}
}
impl ModPowerOf2Mul<&Natural> for &NaturalVector {
type Output = NaturalVector;
/// Multiplies every element of a [`NaturalVector`] by a [`Natural`] modulo $2^k$, taking the
/// vector by reference and the scalar by reference. The elements and the scalar must already be
/// reduced modulo $2^k$.
///
/// See the documentation for the [`ModPowerOf2Mul`] implementation that takes the vector and
/// the scalar by value for details.
///
/// # Worst-case complexity
/// $T(n, m) = O(nm \log m \log\log m)$
///
/// $M(n, m) = O(nm)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is `self.dimension()`, and $m$ is `pow`.
///
/// # Panics
/// Panics if any element of `self`, or `c`, is greater than or equal to $2^k$.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::ModPowerOf2Mul;
/// use malachite_nz::natural::Natural;
/// use malachite_nz::natural_vector::NaturalVector;
///
/// let v = NaturalVector::from_str("(5, 1, 3)").unwrap();
/// assert_eq!(
/// (&v).mod_power_of_2_mul(&Natural::from(3u32), 3).to_string(),
/// "(7, 3, 1)"
/// );
/// ```
fn mod_power_of_2_mul(self, c: &Natural, pow: u64) -> NaturalVector {
assert_reduced(self, c, pow);
NaturalVector {
elements: match *c {
Natural::ZERO => vec![Natural::ZERO; self.elements.len()],
Natural::ONE => self.elements.clone(),
_ => self
.elements
.iter()
.map(|x| x.mod_power_of_2_mul(c, pow))
.collect(),
},
}
}
}
impl ModPowerOf2MulAssign<Natural> for NaturalVector {
/// Multiplies every element of a [`NaturalVector`] by a [`Natural`] modulo $2^k$, in place,
/// taking the scalar by value. The elements and the scalar must already be reduced modulo
/// $2^k$.
///
/// See the documentation for the [`ModPowerOf2Mul`] implementation that takes the vector and
/// the scalar by value for details.
///
/// # Worst-case complexity
/// $T(n, m) = O(nm \log m \log\log m)$
///
/// $M(n, m) = O(m \log m)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is `self.dimension()`, and $m$ is `pow`.
///
/// # Panics
/// Panics if any element of `self`, or `c`, is greater than or equal to $2^k$.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::ModPowerOf2MulAssign;
/// use malachite_nz::natural::Natural;
/// use malachite_nz::natural_vector::NaturalVector;
///
/// let mut v = NaturalVector::from_str("(5, 1, 3)").unwrap();
/// v.mod_power_of_2_mul_assign(Natural::from(3u32), 3);
/// assert_eq!(v.to_string(), "(7, 3, 1)");
/// ```
#[inline]
fn mod_power_of_2_mul_assign(&mut self, c: Natural, pow: u64) {
self.mod_power_of_2_mul_assign(&c, pow);
}
}
impl ModPowerOf2MulAssign<&Natural> for NaturalVector {
/// Multiplies every element of a [`NaturalVector`] by a [`Natural`] modulo $2^k$, in place,
/// taking the scalar by reference. The elements and the scalar must already be reduced modulo
/// $2^k$.
///
/// See the documentation for the [`ModPowerOf2Mul`] implementation that takes the vector and
/// the scalar by value for details.
///
/// # Worst-case complexity
/// $T(n, m) = O(nm \log m \log\log m)$
///
/// $M(n, m) = O(m \log m)$
///
/// where $T$ is time, $M$ is additional memory, $n$ is `self.dimension()`, and $m$ is `pow`.
///
/// # Panics
/// Panics if any element of `self`, or `c`, is greater than or equal to $2^k$.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::ModPowerOf2MulAssign;
/// use malachite_nz::natural::Natural;
/// use malachite_nz::natural_vector::NaturalVector;
///
/// let mut v = NaturalVector::from_str("(5, 1, 3)").unwrap();
/// v.mod_power_of_2_mul_assign(&Natural::from(3u32), 3);
/// assert_eq!(v.to_string(), "(7, 3, 1)");
/// ```
fn mod_power_of_2_mul_assign(&mut self, c: &Natural, pow: u64) {
assert_reduced(self, c, pow);
match *c {
Natural::ZERO => self.elements.fill(Natural::ZERO),
Natural::ONE => {}
_ => {
for x in &mut self.elements {
x.mod_power_of_2_mul_assign(c, pow);
}
}
}
}
}