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1995eaton/is_prime.js

Created July 3, 2016 14:03
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Regex prime test
Raw
is_prime.js
function isPrime(n) {
if (n <= 1)
return false;
var pattern = new RegExp('^(.{2,' + Math.ceil(Math.sqrt(n)) + '})\\1+$');
return !pattern.test('.'.repeat(n));
}
var n = ~~process.argv[2];
console.log(`${n} ${isPrime(n) ? 'is' : 'is not'} prime`);
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