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- #!/usr/bin/ruby
- # Author: Trizen
- # Date: 18 March 2023
- # https://github.com/trizen
- # https://projecteuler.net/problem=60
- # Runtime: 21.765s
- var primes = 1e4.primes
- say "Checking primes <= #{primes.tail}"
- primes.each_kv {|i,p|
- var indx = []
- var good = [p]
- for (var j = i+1; true; ++j) {
- var q = primes[j] \\ do {
- break if indx.is_empty
- good.pop
- j = indx.pop
- next
- }
- var ok = true
- [q, good...].combinations(2, {|*a|
- (a.join.to_n.is_prime && a.flip.join.to_n.is_prime) || do {
- ok = false
- break
- }
- })
- if (ok) {
- good << q
- indx << j
- if (good.len == 5) {
- say "sum(#{good}) = #{good.sum}"
- goto :FINISH
- }
- }
- }
- } @:FINISH
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