47 lines
1.7 KiB
Rust
47 lines
1.7 KiB
Rust
use std::collections::HashSet;
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fn main() {
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// Use command line arguments to specify the input filename.
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let args: Vec<String> = std::env::args().collect();
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if args.len() < 2 {
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panic!("Usage: ./main <input-file>\nNo input file provided. Exiting.");
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}
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// Next, read the contents of the input file into a string for easier processing.
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let input = std::fs::read_to_string(&args[1]).expect("Error opening file");
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// Line-by-line processing is easiest.
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let input = input.lines();
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// --- TASK BEGIN ---
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let mut count = 0;
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for line in input {
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// Turn "1-2,3-6" into ["1-2", "3-6"].
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let ranges = line.split(',').collect::<Vec<_>>();
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// Turn ["1-2", "3-6"] into [["1", "2"], ["3", "6"]]
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let ranges = ranges
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.iter()
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.map(|x| x.split('-').collect::<Vec<_>>())
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.collect::<Vec<_>>();
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// Turn [["1", "2"], ["3", "6"]] into [1..=2, 3..=6]
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let ranges = ranges
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.iter()
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.map(|x| (x[0].parse::<i32>().unwrap())..=(x[1].parse::<i32>().unwrap()))
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.collect::<Vec<_>>();
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// Now turn the ranges into HashSets containing the respective integers. Essentially:
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// Turn [1..=2, 3..=6] into [{1,2}, {3,4,5,6}]
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let sets = ranges
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.into_iter()
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.map(|x| x.collect::<HashSet<_>>())
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.collect::<Vec<_>>();
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// Check if either of the sets is a subset of the other, i.e. is fully contained in the other.
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// If so, add it to the count.
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if sets[0].is_subset(&sets[1]) || sets[1].is_subset(&sets[0]) {
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count += 1;
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}
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}
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println!("Count: {}", count);
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}
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