pub fn intersperse<A: Clone, F: Fn(usize) -> A>(as: &[A], separator: F) -> Vec<A> {
let mut result = Vec::with_capacity(as.len() * 2);
for (i, a) in as.iter().enumerate() {
if i > 0 {
result.push(separator(i));
}
result.push(a.clone());
}
result
}
pub fn count<T, F>(arr: &[T], pred: F) -> usize
where
F: Fn(&T) -> bool,
{
arr.iter().filter(|x| pred(x)).count()
}
pub fn uniq<T: std::hash::Hash + Eq + Clone>(xs: impl IntoIterator<Item = T>) -> Vec<T> {
let mut set = std::collections::HashSet::new();
let mut result = Vec::new();
for x in xs {
if set.insert(x.clone()) {
result.push(x);
}
}
result
}