1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59
use crate::common::*; #[derive(Debug, Clone, Copy, PartialOrd, Ord, PartialEq, Eq, Hash, Default)] pub struct MinCollector<A>(pub Option<A>); impl<A> FromIterator<A> for MinCollector<A> where A: Ord, { fn from_iter<T: IntoIterator<Item = A>>(iter: T) -> Self { let min = iter.into_iter().fold1(|lhs, rhs| lhs.min(rhs)); Self(min) } } impl<A> MinCollector<A> { pub fn unwrap(self) -> A { self.0.unwrap() } pub fn get(self) -> Option<A> { self.0 } } impl<A> From<MinCollector<A>> for Option<A> { fn from(collector: MinCollector<A>) -> Self { collector.0 } } impl<A> Extend<A> for MinCollector<A> where A: Ord, { fn extend<T: IntoIterator<Item = A>>(&mut self, iter: T) { let min = self .0 .take() .into_iter() .chain(iter) .fold1(|lhs, rhs| lhs.min(rhs)); self.0 = min; } } #[cfg(test)] mod tests { use super::*; #[test] fn min_test() { let mut min: MinCollector<isize> = (1..100).collect(); assert_eq!(min.unwrap(), 1); min.extend((-200)..(-100)); assert_eq!(min.unwrap(), -200); } }