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use cargo_snippet::snippet;
#[snippet("bitset")]
#[derive(Debug, Copy, Clone)]
pub struct BitSet {
size: usize,
}
#[snippet("bitset")]
impl BitSet {
pub fn new(n: usize) -> Self {
Self { size: n }
}
pub fn len(&self) -> usize {
self.size
}
pub fn combinations(&self) -> usize {
1 << self.size
}
}
#[snippet("bitset")]
impl IntoIterator for BitSet {
type Item = Vec<bool>;
type IntoIter = IntoIterBitSet;
fn into_iter(self) -> Self::IntoIter {
IntoIterBitSet {
size: self.len(),
current: 0,
}
}
}
#[snippet("bitset")]
#[derive(Copy, Clone, Debug)]
pub struct IntoIterBitSet {
size: usize,
current: usize,
}
#[snippet("bitset")]
impl Iterator for IntoIterBitSet {
type Item = Vec<bool>;
fn next(&mut self) -> Option<Self::Item> {
if self.current == (1 << self.size) {
None
} else {
let res = Some(
(0..self.size)
.rev()
.map(|x| self.current & (1 << x) != 0)
.collect::<Vec<_>>(),
);
self.current += 1;
res
}
}
}
#[test]
fn bs_iter() {
let mut bs = BitSet::new(3).into_iter();
assert_eq!(Some(vec![false, false, false]), bs.next());
assert_eq!(Some(vec![false, false, true]), bs.next());
assert_eq!(Some(vec![false, true, false]), bs.next());
assert_eq!(Some(vec![false, true, true]), bs.next());
assert_eq!(Some(vec![true, false, false]), bs.next());
assert_eq!(Some(vec![true, false, true]), bs.next());
assert_eq!(Some(vec![true, true, false]), bs.next());
assert_eq!(Some(vec![true, true, true]), bs.next());
assert_eq!(None, bs.next());
}
#[snippet("bitset")]
pub trait BitsOps {
fn count_zeros(&self) -> usize;
fn count_ones(&self) -> usize;
fn grow(&mut self, bits: usize);
fn put(&mut self, bits: usize) -> bool;
fn toggle(&mut self, bit: usize);
fn set(&mut self, bit: usize, into: bool);
fn shl(&mut self, rhs: usize);
fn shr(&mut self, rhs: usize);
}
#[snippet("bitset")]
impl BitsOps for Vec<bool> {
fn count_zeros(&self) -> usize {
self.iter().filter(|x| **x).count()
}
fn count_ones(&self) -> usize {
self.iter().filter(|x| !**x).count()
}
fn grow(&mut self, bits: usize) {
self.reverse();
self.append(&mut vec![false; bits]);
self.reverse();
}
fn put(&mut self, bits: usize) -> bool {
let prev = self[bits];
self[bits] = true;
prev
}
fn toggle(&mut self, bit: usize) {
self[bit] = !self[bit];
}
fn set(&mut self, bit: usize, into: bool) {
self[bit] = into;
}
fn shl(&mut self, rhs: usize) {
self.append(&mut vec![false; rhs]);
}
fn shr(&mut self, rhs: usize) {
let len = self.len();
let mut res = vec![false; rhs];
res.append(&mut self[..len - rhs].to_vec());
*self = res;
}
}