extern crate itertools; // 0.8.0

use std::collections::BTreeSet;

use itertools::Itertools;

fn main() {
    let input = vec!["eat", "tea", "tan", "ate", "nat", "bat"];
    for group in input.iter().map(|v| (v.chars().collect::<BTreeSet<char>>(), v)).into_group_map().values() {
        println!("{:?}", group);
    }
}