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use core::cmp::Ordering;
use super::ArrayArgReduce;
#[const_trait]
pub trait ArrayArgMinMax<T, const N: usize>: ArrayArgReduce<T, N>
{
/// Finds the index of the maximum value in the slice.
///
/// If there are multiple maxima, only the first will have its index returned.
///
/// # Example
///
/// ```rust
/// use array__ops::ops::*;
///
/// // v
/// let x = [1, 5, 5, 6, 2, -1, 0, -4, -1, 6];
///
/// let i = x.argmax().unwrap();
///
/// assert_eq!(i, 3);
/// ```
fn argmax(&self) -> Option<usize>
where
T: PartialOrd<T>;
/// Finds the index of the minimum value in the slice.
///
/// If there are multiple minimums, only the first will have its index returned.
///
/// # Example
///
/// ```rust
/// use array__ops::ops::*;
///
/// // v
/// let x = [1, 5, 5, 6, 2, -1, 0, -4, -1, 6];
///
/// let i = x.argmin().unwrap();
///
/// assert_eq!(i, 7);
/// ```
fn argmin(&self) -> Option<usize>
where
T: PartialOrd<T>;
/// Finds the index of the maximum value in the slice, given a comparison predicate.
///
/// If there are multiple maxima, only the first will have its index returned.
///
/// # Example
///
/// ```rust
/// use array__ops::ops::*;
///
/// // v
/// let x = [1, 5, 5, 6, 2, -1, 0, -4, -1, 6];
///
/// let f = Ord::cmp;
///
/// let i = x.argmax_by(f).unwrap();
///
/// assert_eq!(i, 3);
/// ```
fn argmax_by<'a, F>(&'a self, f: F) -> Option<usize>
where
F: FnMut(&'a T, &'a T) -> Ordering /*+ ~const Destruct*/,
T: 'a;
/// Finds the index of the minimum value in the slice, given a comparison predicate.
///
/// If there are multiple minimums, only the first will have its index returned.
///
/// # Example
///
/// ```rust
/// use array__ops::ops::*;
///
/// // v
/// let x = [1, 5, 5, 6, 2, -1, 0, -4, -1, 6];
///
/// let f = Ord::cmp;
///
/// let i = x.argmin_by(f).unwrap();
///
/// assert_eq!(i, 7);
/// ```
fn argmin_by<'a, F>(&'a self, f: F) -> Option<usize>
where
F: FnMut(&'a T, &'a T) -> Ordering /*+ ~const Destruct*/,
T: 'a;
/// Finds the index of the maximum key in the slice, given a hashing function.
///
/// If there are multiple maxima, only the first will have its index returned.
///
/// # Example
///
/// ```rust
/// use array__ops::ops::*;
///
/// // v
/// let x = ["1", "5", "5", "6", "2", "-1", "0", "-4", "-1", "6"];
///
/// let f = |&e| i32::from_str_radix(e, 10).unwrap();
///
/// let i = x.argmax_by_key(f).unwrap();
///
/// assert_eq!(i, 3);
/// ```
fn argmax_by_key<'a, B, F>(&'a self, f: F) -> Option<usize>
where
F: FnMut(&'a T) -> B /*+ ~const Destruct*/,
B: PartialOrd,
T: 'a;
/// Finds the index of the minimum key in the slice, given a hashing function.
///
/// If there are multiple minimums, only the first will have its index returned.
///
/// # Example
///
/// ```rust
/// use array__ops::ops::*;
///
/// // v
/// let x = ["1", "5", "5", "6", "2", "-1", "0", "-4", "-1", "6"];
///
/// let f = |&e| i32::from_str_radix(e, 10).unwrap();
///
/// let i = x.argmin_by_key(f).unwrap();
///
/// assert_eq!(i, 7);
/// ```
fn argmin_by_key<'a, B, F>(&'a self, f: F) -> Option<usize>
where
F: FnMut(&'a T) -> B /*+ ~const Destruct*/,
B: PartialOrd,
T: 'a;
}
impl<T, const N: usize> ArrayArgMinMax<T, N> for [T; N]
{
fn argmax(&self) -> Option<usize>
where
T: PartialOrd<T>
{
self.argreduce(PartialOrd::gt)
}
fn argmin(&self) -> Option<usize>
where
T: PartialOrd<T>
{
self.argreduce(PartialOrd::lt)
}
fn argmax_by<'a, F>(&'a self, mut f: F) -> Option<usize>
where
F: FnMut(&'a T, &'a T) -> Ordering,
T: 'a
{
self.argreduce(|a, b| matches!(f(a, b), Ordering::Greater))
}
fn argmin_by<'a, F>(&'a self, mut f: F) -> Option<usize>
where
F: FnMut(&'a T, &'a T) -> Ordering,
T: 'a
{
self.argreduce(|a, b| matches!(f(a, b), Ordering::Less))
}
fn argmax_by_key<'a, B, F>(&'a self, f: F) -> Option<usize>
where
F: FnMut(&'a T) -> B,
B: PartialOrd,
T: 'a
{
self.argreduce_key(PartialOrd::gt, f)
}
fn argmin_by_key<'a, B, F>(&'a self, f: F) -> Option<usize>
where
F: FnMut(&'a T) -> B,
B: PartialOrd,
T: 'a
{
self.argreduce_key(PartialOrd::lt, f)
}
}