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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::integer_polynomial::IntegerPolynomial;
use malachite_base::num::arithmetic::traits::{
CanonicalizeUnit, CanonicalizeUnitAssign, NegAssign,
};
use malachite_base::polynomial::Polynomial;
impl CanonicalizeUnit for IntegerPolynomial {
type Output = Self;
/// Brings an [`IntegerPolynomial`] into canonical unit form, taking it by value.
///
/// The canonical associate is the one whose leading coefficient is non-negative, so a
/// polynomial with a negative leading coefficient is negated and any other is left alone. The
/// zero polynomial is its own canonical associate.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(1)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.len()`.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::CanonicalizeUnit;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer_polynomial::IntegerPolynomial;
///
/// assert_eq!(
/// IntegerPolynomial::from_str("-3*x^2+2")
/// .unwrap()
/// .canonicalize_unit()
/// .to_string(),
/// "3*x^2-2"
/// );
/// assert_eq!(
/// IntegerPolynomial::from_str("3*x^2-2")
/// .unwrap()
/// .canonicalize_unit()
/// .to_string(),
/// "3*x^2-2"
/// );
/// assert_eq!(
/// IntegerPolynomial::ZERO.canonicalize_unit(),
/// IntegerPolynomial::ZERO
/// );
/// ```
#[inline]
fn canonicalize_unit(mut self) -> Self {
self.canonicalize_unit_assign();
self
}
}
impl CanonicalizeUnit for &IntegerPolynomial {
type Output = IntegerPolynomial;
/// Brings an [`IntegerPolynomial`] into canonical unit form, taking it by reference.
///
/// The canonical associate is the one whose leading coefficient is non-negative, so a
/// polynomial with a negative leading coefficient is negated and any other is left alone. The
/// zero polynomial is its own canonical associate.
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(n)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is the total size of the coefficients.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::CanonicalizeUnit;
/// use malachite_base::num::basic::traits::Zero;
/// use malachite_nz::integer_polynomial::IntegerPolynomial;
///
/// assert_eq!(
/// (&IntegerPolynomial::from_str("-3*x^2+2").unwrap())
/// .canonicalize_unit()
/// .to_string(),
/// "3*x^2-2"
/// );
/// assert_eq!(
/// (&IntegerPolynomial::from_str("3*x^2-2").unwrap())
/// .canonicalize_unit()
/// .to_string(),
/// "3*x^2-2"
/// );
/// assert_eq!(
/// (&IntegerPolynomial::ZERO).canonicalize_unit(),
/// IntegerPolynomial::ZERO
/// );
/// ```
#[inline]
fn canonicalize_unit(self) -> IntegerPolynomial {
if *self.leading_coefficient() < 0u32 {
-self
} else {
self.clone()
}
}
}
impl CanonicalizeUnitAssign for IntegerPolynomial {
/// Brings an [`IntegerPolynomial`] into canonical unit form, in place.
///
/// See [`canonicalize_unit`](CanonicalizeUnit::canonicalize_unit).
///
/// # Worst-case complexity
/// $T(n) = O(n)$
///
/// $M(n) = O(1)$
///
/// where $T$ is time, $M$ is additional memory, and $n$ is `self.len()`.
///
/// # Examples
/// ```
/// use core::str::FromStr;
/// use malachite_base::num::arithmetic::traits::CanonicalizeUnitAssign;
/// use malachite_nz::integer_polynomial::IntegerPolynomial;
///
/// let mut p = IntegerPolynomial::from_str("-3*x^2+2").unwrap();
/// p.canonicalize_unit_assign();
/// assert_eq!(p.to_string(), "3*x^2-2");
/// ```
#[inline]
fn canonicalize_unit_assign(&mut self) {
if *self.leading_coefficient() < 0u32 {
self.neg_assign();
}
}
}