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33 lines
854 B
33 lines
854 B
use failure::*;
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#[allow(dead_code)]
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pub fn solve(input: &str) -> Result<String, Error> {
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let input: Vec<u32> = input
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.trim()
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.chars()
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.map(|x| x.to_digit(10).ok_or_else(|| err_msg("")))
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.collect::<Result<_, _>>()?;
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// 1
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// let offset = 1;
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let offset = input.len() / 2;
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let offset_iter = input.iter().cycle().skip(offset);
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Ok(input
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.iter()
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.zip(offset_iter)
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.filter(|&a| a.0 == a.1)
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.map(|a| a.0)
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.sum::<u32>()
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.to_string())
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}
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#[test]
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fn part_two() {
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assert_eq!(solve("1212").unwrap(), "6".to_string());
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assert_eq!(solve("1221").unwrap(), "0".to_string());
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assert_eq!(solve("123425").unwrap(), "4".to_string());
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assert_eq!(solve("123123").unwrap(), "12".to_string());
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assert_eq!(solve("12131415").unwrap(), "4".to_string());
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}
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