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use std::collections::HashMap;
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use std::collections::hash_map::Entry;
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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 mut jumps: HashMap<isize, isize> = input
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.trim()
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.lines()
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.enumerate()
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.map(|(i,x)| x.parse().map(|x| (i as isize, x)))
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.collect::<Result<_,_>>()?;
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let mut pc = 0;
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let mut steps = 0;
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while let Entry::Occupied(mut entry) = jumps.entry(pc) {
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let offset = entry.get_mut();
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pc += *offset;
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if *offset >= 3 {
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*offset -= 1;
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} else {
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*offset += 1;
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}
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steps += 1;
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}
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Ok(steps.to_string())
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}
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