johannes/aoc_2018
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

day01-2 use scan with tuple expansion

Browse Source 
The previous problem with this was, that I tried returning
"Some((Ref<i32>, _))" from the lambda. That caused the compiler to complain
about the lifetime of the `current` value, since I tried passing on the Ref
instead of the encapsulated value.
This commit is contained in:
Johannes
2018-12-01 18:19:07 +01:00
parent 0494dee19d
commit a0509342ae
1 changed files with 9 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
src/tasks/day01.rs
View File

@@ -7,26 +7,23 @@ pub fn task1() {
.map(|line| line.parse::<i32>().unwrap()) .map(|line| line.parse::<i32>().unwrap())
.sum(); .sum();
println!("Result: {}", frequency); println!("Part 1: {}", frequency);
} }
pub fn task2() { pub fn task2() {
let contents = utils::read_file("input/day01.txt"); let start_state = (vec![0].into_iter().collect::<HashSet<i32>>(), 0);
let final_state = utils::read_file("input/day01.txt")
let seen: HashSet<i32> = vec![0].into_iter().collect();
let start_state = (seen, 0);
let final_state = contents
.lines() .lines()
.map(|line| line.parse::<i32>().unwrap()) .map(|line| line.parse::<i32>().unwrap())
.cycle() .cycle()
.scan(start_state, |state, freq_change| { .scan(start_state, |(set, current), freq_change| {
state.1 += freq_change; *current += freq_change;
if state.0.insert(state.1) { if set.insert(*current) {
Some((state.1, false)) Some((*current, false))
} else { } else {
Some((state.1, true)) Some((*current, true))
} }
}).find(|state| state.1); }).find(|state| state.1);
println!("{:?} was there already!", final_state.unwrap().0); println!("Part 2: {} was there already!", final_state.unwrap().0);
} }