[2018][rust][1.1]

sorbet
Alpha Chen 6 years ago
parent bf79c7262e
commit 7ececd84fc

@ -1,6 +1,7 @@
use std::collections::HashMap;
use std::io::{self, Read}; use std::io::{self, Read};
fn day_1(input: &str, delimiter: &str) -> String { fn day_1_0(input: &str, delimiter: &str) -> String {
let sum: i32 = input let sum: i32 = input
.split(delimiter) .split(delimiter)
.flat_map(|change| change.parse::<i32>().ok()) .flat_map(|change| change.parse::<i32>().ok())
@ -9,14 +10,46 @@ fn day_1(input: &str, delimiter: &str) -> String {
} }
#[test] #[test]
fn test_day_1() { fn test_day_1_0() {
assert_eq!(day_1("+1, -2, +3, +1", ", "), "3"); assert_eq!(day_1_0("+1, -2, +3, +1", ", "), "3");
}
fn day_1_1(input: &str, delimiter: &str) -> String {
let mut seen = HashMap::new();
seen.insert(0, 1);
input
.split(delimiter)
.flat_map(|change| change.parse::<i32>().ok())
.cycle()
.scan((seen, 0), |(seen, freq), change| {
*freq += change;
let count = seen.entry(freq.clone()).or_insert(0);
*count += 1;
Some((freq.clone(), count.clone()))
})
.filter(|(_, count)| *count > 1)
.map(|(freq, _)| freq)
.next()
.unwrap()
.to_string()
}
#[test]
fn test_day_1_1() {
assert_eq!(day_1_1("+1, -2, +3, +1", ", "), "2");
assert_eq!(day_1_1("+1, -1", ", "), "0");
assert_eq!(day_1_1("+3, +3, +4, -2, -4", ", "), "10");
assert_eq!(day_1_1("-6, +3, +8, +5, -6", ", "), "5");
assert_eq!(day_1_1("+7, +7, -2, -7, -4", ", "), "14");
} }
fn main() { fn main() {
let mut input = String::new(); let mut input = String::new();
io::stdin().read_to_string(&mut input).unwrap(); io::stdin().read_to_string(&mut input).unwrap();
let output = day_1(&input, "\n"); let output = day_1_1(&input, "\n");
println!("{}", output); println!("{}", output);
} }

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