IterBinomial: Only return coefficient
This commit is contained in:
parent
e486e6a981
commit
47613ff5ff
|
@ -675,7 +675,7 @@ pub struct IterBinomial<T> {
|
|||
impl<T> IterBinomial<T>
|
||||
where T: Integer,
|
||||
{
|
||||
/// For a given n, iterate over all binomial coefficients ((k, n - k), binomial(n, k)).
|
||||
/// For a given n, iterate over all binomial coefficients binomial(n, k), for k=0...n.
|
||||
pub fn new(n: T) -> IterBinomial<T> {
|
||||
IterBinomial {
|
||||
k: T::zero(), a: T::one(), n: n
|
||||
|
@ -686,9 +686,9 @@ impl<T> IterBinomial<T>
|
|||
impl<T> Iterator for IterBinomial<T>
|
||||
where T: Integer + Clone
|
||||
{
|
||||
type Item = ((T, T), T);
|
||||
type Item = T;
|
||||
|
||||
fn next(&mut self) -> Option<((T, T), T)> {
|
||||
fn next(&mut self) -> Option<T> {
|
||||
if self.k > self.n {
|
||||
return None;
|
||||
}
|
||||
|
@ -697,11 +697,8 @@ impl<T> Iterator for IterBinomial<T>
|
|||
} else {
|
||||
T::one()
|
||||
};
|
||||
let r = Some(
|
||||
((self.k.clone(), self.n.clone() - self.k.clone()),
|
||||
self.a.clone()));
|
||||
self.k = self.k.clone() + T::one();
|
||||
r
|
||||
Some(self.a.clone())
|
||||
}
|
||||
}
|
||||
|
||||
|
@ -768,7 +765,7 @@ fn test_binomial_coeff() {
|
|||
($t:ty) => { {
|
||||
let n: $t = 3;
|
||||
let c: Vec<_> = IterBinomial::new(n).collect();
|
||||
let expected = vec![((0, 3), 1), ((1, 2), 3), ((2, 1), 3), ((3, 0), 1)];
|
||||
let expected = vec![1, 3, 3, 1];
|
||||
assert_eq!(c, expected);
|
||||
} }
|
||||
}
|
||||
|
@ -786,8 +783,10 @@ fn test_binomial_coeff() {
|
|||
($t:ty, $n:expr) => { {
|
||||
let n: $t = $n;
|
||||
let c: Vec<_> = IterBinomial::new(n).collect();
|
||||
for &((k, _), b) in &c {
|
||||
let mut k: $t = 0;
|
||||
for b in c {
|
||||
assert_eq!(b, binomial(n, k));
|
||||
k += 1;
|
||||
}
|
||||
} }
|
||||
}
|
||||
|
|
Loading…
Reference in New Issue