Java/src/main/java/com/thealgorithms/maths/AliquotSum.java at master · tyb/Java · GitHub

32 lines (27 loc) · 1003 Bytes

package com.thealgorithms.maths;

import java.util.stream.IntStream;

/**

* In number theory, the aliquot sum s(n) of a positive integer n is the sum of

* all proper divisors of n, that is, all divisors of n other than n itself. For

* example, the proper divisors of 15 (that is, the positive divisors of 15 that

* are not equal to 15) are 1, 3 and 5, so the aliquot sum of 15 is 9 i.e. (1 +

* 3 + 5). Wikipedia: https://en.wikipedia.org/wiki/Aliquot_sum

public class AliquotSum {

/**

* Finds the aliquot sum of an integer number.

* @param number a positive integer

* @return aliquot sum of given {@code number}

public static int getAliquotValue(int number) {

var sumWrapper = new Object() {

int value = 0;

};

IntStream.iterate(1, i -> ++i)

.limit(number / 2)

.filter(i -> number % i == 0)

.forEach(i -> sumWrapper.value += i);

return sumWrapper.value;

}

Expand file tree