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use anyhow::Result;
use std::collections::HashSet;
use std::env::args;
use std::fs::File;
use std::io::{BufRead, BufReader};
use std::path::Path;
fn read_input<T: AsRef<Path>>(filename: T) -> Result<Vec<Vec<String>>> {
let f = File::open(filename)?;
let reader = BufReader::new(f);
let mut group = vec![];
let mut groups = vec![];
for line in reader.lines() {
let line = line?;
if line.is_empty() {
groups.push(group);
group = vec![];
continue;
}
group.push(line);
}
groups.push(group);
Ok(groups)
}
fn part1(input: &[Vec<String>]) -> Option<usize> {
let mut groups = vec![];
for group in input {
let mut set = HashSet::new();
for form in group.iter() {
for answer in form.clone().drain(..) {
set.insert(answer);
}
}
groups.push(set);
}
Some(groups.iter().map(|g| g.len()).sum())
}
fn part2(input: &[Vec<String>]) -> Option<usize> {
let mut groups = vec![];
for group in input {
let sets: Vec<_> = group.iter().map(|form| {
let mut set = HashSet::new();
for answer in form.clone().drain(..) {
set.insert(answer);
}
set
}).collect();
let combined: HashSet<_> = match sets.get(0) {
Some(first) => sets.iter()
.fold(first.clone(), |a, s| s.intersection(&a).cloned().collect()),
None => return None,
};
groups.push(combined);
}
Some(groups.iter().map(|g| g.len()).sum())
}
fn main() {
let (do_part_1, do_part_2) = aoc::do_parts();
let filename = match args().nth(1) {
Some(f) => f,
None => {
eprintln!("Missing input filename");
std::process::exit(1);
},
};
match read_input(filename) {
Ok(input) => {
if do_part_1 {
match part1(&input) {
Some(solution) =>
println!("Part1, sum of all groups combined yes answers: {}", solution),
None => eprintln!("Part1, no soluton found"),
}
}
if do_part_2 {
match part2(&input) {
Some(solution) =>
println!("Part2, sum of all groups common yes answers: {}", solution),
None => eprintln!("Part2, no soluton found"),
}
}
},
Err(err) => eprintln!("Could not read input: {}", err),
}
}
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