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author | Yigit Sever | 2021-12-10 19:54:01 +0300 |
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committer | Yigit Sever | 2021-12-10 19:54:01 +0300 |
commit | 3c97ec63d921c7d2f132a834f9b739cc8d039c99 (patch) | |
tree | 492bbff2312042c68e1a2d2d95ed0bf599dfe545 /2021/day3/src/main.rs | |
parent | ae3853b6e8ab02023ccd74baac6dc177b1ee879a (diff) | |
download | aoc-3c97ec63d921c7d2f132a834f9b739cc8d039c99.tar.gz aoc-3c97ec63d921c7d2f132a834f9b739cc8d039c99.tar.bz2 aoc-3c97ec63d921c7d2f132a834f9b739cc8d039c99.zip |
2021, day3: done
Diffstat (limited to '2021/day3/src/main.rs')
-rw-r--r-- | 2021/day3/src/main.rs | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/2021/day3/src/main.rs b/2021/day3/src/main.rs new file mode 100644 index 0000000..2440a39 --- /dev/null +++ b/2021/day3/src/main.rs | |||
@@ -0,0 +1,99 @@ | |||
1 | use std::env; | ||
2 | use std::fs::File; | ||
3 | use std::io::{BufRead, BufReader}; | ||
4 | |||
5 | fn main() { | ||
6 | let args: Vec<String> = env::args().collect(); | ||
7 | |||
8 | if args.len() != 2 { | ||
9 | eprintln!("Usage: {} filename", args[0]); | ||
10 | std::process::exit(1); | ||
11 | } | ||
12 | |||
13 | let filename = &args[1]; | ||
14 | |||
15 | let file = File::open(filename).unwrap_or_else(|_| panic!("No such file: {}", filename)); | ||
16 | let reader = BufReader::new(file); | ||
17 | |||
18 | let mut numbers: Vec<u32> = Vec::new(); | ||
19 | |||
20 | for line in reader.lines() { | ||
21 | let line = line.unwrap(); | ||
22 | numbers.push(isize::from_str_radix(&line, 2).unwrap().try_into().unwrap()); | ||
23 | } | ||
24 | |||
25 | let mut co2_numbers: Vec<u32> = numbers.clone(); | ||
26 | let mut oxygen: u32 = 0; | ||
27 | let mut co2: u32 = 0; | ||
28 | |||
29 | for bit in (0..12).rev() { | ||
30 | let keep; | ||
31 | let mut one_bits = 0; | ||
32 | let mut zero_bits = 0; | ||
33 | for num in &numbers { | ||
34 | one_bits += (num >> bit) & 1; | ||
35 | zero_bits += ((num >> bit) & 1) ^ 1; | ||
36 | } | ||
37 | |||
38 | println!("for bit: {}", bit); | ||
39 | println!("one_bits: {}", one_bits); | ||
40 | println!("zero_bits: {}", zero_bits); | ||
41 | |||
42 | if zero_bits > one_bits { | ||
43 | keep = 0; | ||
44 | } else if zero_bits < one_bits { | ||
45 | keep = 1; | ||
46 | } else { | ||
47 | keep = 1; | ||
48 | } | ||
49 | |||
50 | println!("keeping {}", keep); | ||
51 | |||
52 | numbers.retain(|num| ((num >> bit) & 1) == keep); | ||
53 | |||
54 | if numbers.len() == 1 { | ||
55 | oxygen = numbers.pop().unwrap(); | ||
56 | break; | ||
57 | } | ||
58 | |||
59 | println!("{:?}", numbers); | ||
60 | } | ||
61 | |||
62 | println!("====co2 now===="); | ||
63 | |||
64 | for bit in (0..12).rev() { | ||
65 | let keep; | ||
66 | let mut one_bits = 0; | ||
67 | let mut zero_bits = 0; | ||
68 | for num in &co2_numbers { | ||
69 | one_bits += (num >> bit) & 1; | ||
70 | zero_bits += ((num >> bit) & 1) ^ 1; | ||
71 | } | ||
72 | |||
73 | println!("for bit: {}", bit); | ||
74 | println!("one_bits: {}", one_bits); | ||
75 | println!("zero_bits: {}", zero_bits); | ||
76 | |||
77 | if zero_bits > one_bits { | ||
78 | keep = 1; | ||
79 | } else if zero_bits < one_bits { | ||
80 | keep = 0; | ||
81 | } else { | ||
82 | keep = 0; | ||
83 | } | ||
84 | |||
85 | println!("keeping {}", keep); | ||
86 | |||
87 | co2_numbers.retain(|num| (num >> bit) & 1 == keep); | ||
88 | |||
89 | if co2_numbers.len() == 1 { | ||
90 | co2 = co2_numbers.pop().unwrap(); | ||
91 | break; | ||
92 | } | ||
93 | |||
94 | println!("{:?}", co2_numbers); | ||
95 | } | ||
96 | |||
97 | println!("oxygen: {}\nco2: {}", oxygen, co2); | ||
98 | println!("answer: {}", oxygen * co2); | ||
99 | } | ||