use std::collections::BTreeSet;
use std::cmp::Ord;
pub trait RebuildInsertion<T> {
fn rebuild_insert(&mut self, T) -> bool;
}
impl<T> RebuildInsertion<T> for BTreeSet<T>
where T: Ord
{
fn rebuild_insert(&mut self, value: T) -> bool {
let flag = self.remove(&value);
self.insert(value);
flag
}
}