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p047.java
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48 lines (38 loc) · 991 Bytes
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/*
* Solution to Project Euler problem 47
* Copyright (c) Project Nayuki. All rights reserved.
*
* https://www.nayuki.io/page/project-euler-solutions
* https://github.com/nayuki/Project-Euler-solutions
*/
public final class p047 implements EulerSolution {
public static void main(String[] args) {
System.out.println(new p047().run());
}
public String run() {
for (int i = 2; ; i++) {
if ( has4PrimeFactors(i + 0)
&& has4PrimeFactors(i + 1)
&& has4PrimeFactors(i + 2)
&& has4PrimeFactors(i + 3))
return Integer.toString(i);
}
}
private static boolean has4PrimeFactors(int n) {
return countDistinctPrimeFactors(n) == 4;
}
private static int countDistinctPrimeFactors(int n) {
int count = 0;
for (int i = 2, end = Library.sqrt(n); i <= end; i++) {
if (n % i == 0) {
do n /= i;
while (n % i == 0);
count++;
end = Library.sqrt(n);
}
}
if (n > 1)
count++;
return count;
}
}