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p037.java
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45 lines (35 loc) · 866 Bytes
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/*
* Solution to Project Euler problem 37
* 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 p037 implements EulerSolution {
public static void main(String[] args) {
System.out.println(new p037().run());
}
public String run() {
long sum = 0;
for (int count = 0, n = 10; count < 11; n++) {
if (isTruncatablePrime(n)) {
sum += n;
count++;
}
}
return Long.toString(sum);
}
private static boolean isTruncatablePrime(int n) {
// Test if left-truncatable
for (long i = 10; i <= n; i *= 10) {
if (!Library.isPrime(n % (int)i))
return false;
}
// Test if right-truncatable
for (; n != 0; n /= 10) {
if (!Library.isPrime(n))
return false;
}
return true;
}
}