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use std::env;
use std::fs::File;
use std::io::{BufRead, BufReader};
fn main() {
let args: Vec<String> = env::args().collect();
if args.len() != 2 {
eprintln!("Usage: {} filename", args[0]);
std::process::exit(1);
}
let filename = &args[1];
let file = File::open(filename).unwrap_or_else(|_| panic!("No such file: {}", filename));
let reader = BufReader::new(file);
let mut numbers: Vec<u32> = Vec::new();
for line in reader.lines() {
let line = line.unwrap();
numbers.push(isize::from_str_radix(&line, 2).unwrap().try_into().unwrap());
}
let mut co2_numbers: Vec<u32> = numbers.clone();
let mut oxygen: u32 = 0;
let mut co2: u32 = 0;
for bit in (0..12).rev() {
let keep;
let mut one_bits = 0;
let mut zero_bits = 0;
for num in &numbers {
one_bits += (num >> bit) & 1;
zero_bits += ((num >> bit) & 1) ^ 1;
}
println!("for bit: {}", bit);
println!("one_bits: {}", one_bits);
println!("zero_bits: {}", zero_bits);
if zero_bits > one_bits {
keep = 0;
} else if zero_bits < one_bits {
keep = 1;
} else {
keep = 1;
}
println!("keeping {}", keep);
numbers.retain(|num| ((num >> bit) & 1) == keep);
if numbers.len() == 1 {
oxygen = numbers.pop().unwrap();
break;
}
println!("{:?}", numbers);
}
println!("====co2 now====");
for bit in (0..12).rev() {
let keep;
let mut one_bits = 0;
let mut zero_bits = 0;
for num in &co2_numbers {
one_bits += (num >> bit) & 1;
zero_bits += ((num >> bit) & 1) ^ 1;
}
println!("for bit: {}", bit);
println!("one_bits: {}", one_bits);
println!("zero_bits: {}", zero_bits);
if zero_bits > one_bits {
keep = 1;
} else if zero_bits < one_bits {
keep = 0;
} else {
keep = 0;
}
println!("keeping {}", keep);
co2_numbers.retain(|num| (num >> bit) & 1 == keep);
if co2_numbers.len() == 1 {
co2 = co2_numbers.pop().unwrap();
break;
}
println!("{:?}", co2_numbers);
}
println!("oxygen: {}\nco2: {}", oxygen, co2);
println!("answer: {}", oxygen * co2);
}
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