Advent of Code solutions
day 2
+107
+7
2025/2/Cargo.lock
+7
2025/2/Cargo.lock
+6
2025/2/Cargo.toml
+6
2025/2/Cargo.toml
+1
2025/2/input.txt
+1
2025/2/input.txt
···
1
+
6161588270-6161664791,128091420-128157776,306-494,510-1079,10977-20613,64552-123011,33-46,28076-52796,371150-418737,691122-766624,115-221,7426210-7504719,819350-954677,7713444-7877541,63622006-63661895,1370-1981,538116-596342,5371-8580,8850407-8965070,156363-325896,47-86,452615-473272,2012-4265,73181182-73335464,1102265-1119187,3343315615-3343342551,8388258268-8388317065,632952-689504,3-22,988344-1007943
+93
2025/2/src/main.rs
+93
2025/2/src/main.rs
···
1
+
fn part1(ranges: Vec<(usize, usize)>) -> usize {
2
+
let mut counter = 0;
3
+
4
+
for (start, end) in ranges {
5
+
for num in start..=end {
6
+
let num_string = num.to_string();
7
+
let (fhalf, lhalf) = num_string.split_at(num_string.len() / 2);
8
+
9
+
if fhalf == lhalf {
10
+
counter += num
11
+
}
12
+
}
13
+
}
14
+
15
+
counter
16
+
}
17
+
18
+
fn part2(ranges: Vec<(usize, usize)>) -> usize {
19
+
let mut counter = 0;
20
+
21
+
for (start, end) in ranges {
22
+
'outer: for num in start..=end {
23
+
let num_string = num.to_string();
24
+
let len = num_string.len();
25
+
26
+
// we'll only check up to the half way mark since after that it cant possibly repeat
27
+
for i in 0..=(len / 2) {
28
+
let substring_len = i + 1;
29
+
// i kinda wanted to get rid of the second check but cant bc of nums with 2 digits
30
+
if len % substring_len == 0 && len != substring_len {
31
+
if num_string == num_string.get(0..=i).unwrap().repeat(len / substring_len) {
32
+
counter += num;
33
+
continue 'outer;
34
+
}
35
+
}
36
+
}
37
+
}
38
+
}
39
+
40
+
counter
41
+
}
42
+
43
+
fn main() {
44
+
let file_contents = std::fs::read_to_string("./input.txt").expect("unable to read file");
45
+
let ranges: Vec<(usize, usize)> = file_contents
46
+
.split(',')
47
+
.map(|r| r.split_once('-').unwrap())
48
+
.map(|(lhs, rhs)| (lhs.parse::<usize>().unwrap(), rhs.parse::<usize>().unwrap()))
49
+
.collect();
50
+
51
+
println!("Part 1 Results: {}", part1(ranges.clone()));
52
+
println!("Part 2 Results: {}", part2(ranges));
53
+
}
54
+
55
+
mod tests {
56
+
#[test]
57
+
fn part1() {
58
+
let ranges = vec![
59
+
(11, 22),
60
+
(95, 115),
61
+
(998, 1012),
62
+
(1188511880, 1188511890),
63
+
(222220, 222224),
64
+
(1698522, 1698528),
65
+
(446443, 446449),
66
+
(38593856, 38593862),
67
+
(565653, 565659),
68
+
(824824821, 824824827),
69
+
(2121212118, 2121212124),
70
+
];
71
+
72
+
assert_eq!(super::part1(ranges), 1227775554);
73
+
}
74
+
75
+
#[test]
76
+
fn part2() {
77
+
let ranges = vec![
78
+
(11, 22),
79
+
(95, 115),
80
+
(998, 1012),
81
+
(1188511880, 1188511890),
82
+
(222220, 222224),
83
+
(1698522, 1698528),
84
+
(446443, 446449),
85
+
(38593856, 38593862),
86
+
(565653, 565659),
87
+
(824824821, 824824827),
88
+
(2121212118, 2121212124),
89
+
];
90
+
91
+
assert_eq!(super::part2(ranges), 4174379265);
92
+
}
93
+
}