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16 lines
417 B
16 lines
417 B
use std::collections::HashSet; |
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fn main() { |
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let mut ps = HashSet::new(); |
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let mut hs = HashSet::new(); |
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let N = 500000u64; |
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for n in 1..N { hs.insert(n*(2*n-1)); } |
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for n in 1..N { ps.insert(n*(3*n -1)/2 ); } |
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for n in 286u64..N { |
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let tn = n * (n+1)/2; |
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if !hs.contains(&tn) { continue; } |
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if !ps.contains(&tn) { continue; } |
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println!("{}", tn); |
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break; |
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} |
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}
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