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Add tests for EulersFunction (#4216)

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This commit is contained in:
Piotr Idzik
2023-06-19 19:46:54 +02:00
committed by GitHub
parent e29a22770b
commit 87d6083bac
2 changed files with 56 additions and 13 deletions
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30
src/main/java/com/thealgorithms/others/EulersFunction.java
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@ -1,17 +1,27 @@
package com.thealgorithms.others;
/**
* You can read more about Euler's totient function
*
* <p>
* See https://en.wikipedia.org/wiki/Euler%27s_totient_function
* @brief utility class for <a href="https://en.wikipedia.org/wiki/Euler%27s_totient_function">Euler's totient function</a>
*/
public class EulersFunction {
final public class EulersFunction {
private EulersFunction() {
}
// This method returns us number of x that (x < n) and gcd(x, n) == 1 in O(sqrt(n)) time
// complexity;
private static void checkInput(int n) {
if (n <= 0) {
throw new IllegalArgumentException("n must be positive.");
}
}
/**
* @brief computes the value of Euler's totient function for given input
* @details has time complexity of O(sqrt(n))
* @param n the input
* @exception IllegalArgumentException n is non-positive
* @return the value of Euler's totient function for the input
*/
public static int getEuler(int n) {
checkInput(n);
int result = n;
for (int i = 2; i * i <= n; i++) {
if (n % i == 0) {
@ -26,10 +36,4 @@ public class EulersFunction {
}
return result;
}
public static void main(String[] args) {
for (int i = 1; i < 100; i++) {
System.out.println(getEuler(i));
}
}
}