[2018][rust][1] move day 1 into a module

sorbet
Alpha Chen 6 years ago
parent 7eae195b2a
commit 4919c00a1b

@ -0,0 +1,51 @@
use std::collections::HashMap;
pub fn solve_0(input: &str, delimiter: &str) -> String {
let sum: i32 = input
.trim()
.split(delimiter)
.map(|change| change.parse::<i32>().unwrap())
.sum();
sum.to_string()
}
#[test]
fn test_solve_0() {
assert_eq!(solve_0("+1, -2, +3, +1", ", "), "3");
}
pub fn solve_1(input: &str, delimiter: &str) -> String {
vec![0 as i32] // Start with 0 frequency
.into_iter()
.chain(
input
.trim()
.split(delimiter)
.map(|change| change.parse::<i32>().unwrap())
.cycle(),
)
.scan(0, |freq, change| {
*freq += change;
Some(*freq)
})
.scan(HashMap::new(), |history, freq| {
let count = history.entry(freq).or_insert(0);
*count += 1;
Some((freq, *count))
})
.filter(|(_, count)| *count > 1)
.map(|(freq, _)| freq)
.next()
.unwrap()
.to_string()
}
#[test]
fn test_solve_1() {
assert_eq!(solve_1("+1, -2, +3, +1", ", "), "2");
assert_eq!(solve_1("+1, -1", ", "), "0");
assert_eq!(solve_1("+3, +3, +4, -2, -4", ", "), "10");
assert_eq!(solve_1("-6, +3, +8, +5, -6", ", "), "5");
assert_eq!(solve_1("+7, +7, -2, -7, -4", ", "), "14");
}

@ -1,58 +1,11 @@
use std::collections::HashMap;
use std::io::{self, Read}; use std::io::{self, Read};
fn day_1_0(input: &str, delimiter: &str) -> String { mod day_01;
let sum: i32 = input
.split(delimiter)
.flat_map(|change| change.parse::<i32>().ok())
.sum();
sum.to_string()
}
#[test]
fn test_day_1_0() {
assert_eq!(day_1_0("+1, -2, +3, +1", ", "), "3");
}
fn day_1_1(input: &str, delimiter: &str) -> String {
vec![0 as i32] // Start with 0 frequency
.into_iter()
.chain(
input
.split(delimiter)
.map(|change| change.parse::<i32>().unwrap())
.cycle(),
)
.scan(0, |freq, change| {
*freq += change;
Some(*freq)
})
.scan(HashMap::new(), |history, freq| {
let count = history.entry(freq).or_insert(0);
*count += 1;
Some((freq, *count))
})
.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_1(&input, "\n"); let output = day_01::solve_1(&input, "\n");
println!("{}", output); println!("{}", output);
} }

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