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type Reports = Vec<Vec<i32>>;
fn parse_input(data: &str) -> Reports {
data.lines()
.map(|line| {
line.split(" ")
.map(|x| x.parse::<i32>().unwrap())
.collect::<Vec<i32>>()
})
.collect()
}
fn is_safe_recursive(report: &[i32]) -> bool {
match report {
[] => false,
[_] => false,
[a, b] => (1..=3).contains(&(a - b).abs()),
[a, b, rest @ ..] => (1..=3).contains(&(a - b).abs()) && is_safe_recursive(rest),
}
}
fn is_safe(report: &Vec<i32>) -> bool {
let increasing = report[0] < report[1];
for i in 0..report.len() - 1 {
if increasing {
let diff = report[i + 1] - report[i];
if report[i] >= report[i + 1] || diff > 3 || diff < 1 {
return false;
}
} else {
let diff = report[i] - report[i + 1];
if report[i] <= report[i + 1] || diff > 3 || diff < 1 {
return false;
}
}
}
return true;
}
fn solve_part_one(data: &str) -> usize {
let reports = parse_input(data);
reports.iter().filter(|&report| is_safe(report)).count()
}
fn solve_part_two(data: &str) -> usize {
let reports = parse_input(data);
let mut cnt: usize = 0;
reports
.iter()
.filter(|&report| !is_safe(report))
.for_each(|report| {
for i in 0..report.len() {
let mut report_copy = report.clone();
report_copy.remove(i);
if is_safe(&report_copy) {
cnt += 1;
break;
}
}
});
cnt + reports.iter().filter(|&report| is_safe(report)).count()
}
fn main() {
let test_1 = include_str!("../input/day_2.test");
let prod = include_str!("../input/day_2.prod");
println!("part_1 test: {:?}", solve_part_one(test_1));
println!("part_1 prod {:?}", solve_part_one(prod));
println!("part_2 test: {:?}", solve_part_two(test_1));
println!("part_2 prod {:?}", solve_part_two(prod));
}
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