Day 6 solution

Dependencies

• [2] B527MN66 Solve day 1 for 2020

Change contents

• file addition: day6.rs (----------)
  [2.17]
  + use std::collections::HashSet;

  +

  + struct GroupedLines<I> {

  + inner: I,

  + }

  +

  + impl<I> GroupedLines<I> {

  + fn new(inner: I) -> Self {

  + GroupedLines { inner: inner }

  + }

  + }

  +

  + impl<I: Iterator<Item=S>, S: AsRef<str>> Iterator for GroupedLines<I> {

  + type Item = Vec<String>;

  + fn next(&mut self) -> Option<Self::Item> {

  + let mut r = Vec::new();

  + loop {

  + match self.inner.next() {

  + Some(l) => {

  + if l.as_ref().len() == 0 {

  + break;

  + } else {

  + r.push(String::from(l.as_ref()));

  + }

  + },

  + None => break,

  + }

  + };

  + if r.len() == 0 {

  + None

  + } else {

  + Some(r)

  + }

  + }

  + }

  +

  + fn any_checked(input: Vec<String>) -> HashSet<char> {

  + input.iter().flat_map(|l| l.chars()).collect()

  + }

  +

  + fn all_checked(input: Vec<String>) -> HashSet<char> {

  + let mut i = input.iter();

  + match i.next() {

  + None => HashSet::new(),

  + Some(l0) => {

  + let mut r: HashSet<char> = l0.chars().collect();

  + for l in i {

  + r = r.intersection(&l.chars().collect()).map(Clone::clone).collect();

  + }

  + r

  + },

  + }

  + }

  +

  + fn main() {

  + use std::env;

  + use std::io::BufRead;

  + let args: Vec<_> = env::args().collect();

  + let counts: usize = GroupedLines::new(

  + std::io::BufReader::new(std::fs::File::open(&args[1]).unwrap()).lines()

  + .map(Result::unwrap)

  + ).map(match args[2].as_ref() {

  + "any" => any_checked,

  + "all" => all_checked,

  + _ => panic!("No such aggregator"),

  + })

  + .map(|c| c.len())

  + .sum();

  + println!("{}", counts);

  + }

  +