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Problem47.js
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Problem47.js
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/*
* Prompt: Find the first four consecutive integers to have four distinct prime factors each. What is the first of these numbers?
*
* Execute: node Problem47.js
*
* Answer: 134043
*/
const THRESHOLD = 4;
// From https://gist.github.com/jonathanmarvens/7206278
function primeFactorization(number, result) {
var result = (result || []);
var root = Math.sqrt(number);
var x = 2;
if (number % x) {
x = 3;
while ((number % x) && ((x = (x + 2)) < root)) {}
}
x = (x <= root) ? x : number;
result.push(x);
return (x === number) ? result : primeFactorization((number / x), result);
}
function countDistinct(nFactors, min = THRESHOLD) {
var count = nFactors.reduce(function(values, v) {
if (!values.set[v]) {
values.set[v] = 1;
values.count++;
}
return values;
}, { set: {}, count: 0 }).count;
return count >= min;
}
for (var i = 1; true; i++) {
var commonFactors = { count : 0 };
var factors = primeFactorization(i);
if (!countDistinct(factors))
continue;
var bFactors = primeFactorization(i + 1);
if (!countDistinct(bFactors))
continue;
var cFactors = primeFactorization(i + 2);
if (!countDistinct(cFactors))
continue;
var dFactors = primeFactorization(i + 3);
if (!countDistinct(dFactors))
continue;
console.log(i);
return;
}