Java/Maths/AliquotSum.java at master · loisoft/Java · GitHub

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package Maths;

/**

* 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 {

public static void main(String[] args) {

assert aliquotSum(1) == 0;

assert aliquotSum(6) == 6;

assert aliquotSum(15) == 9;

assert aliquotSum(19) == 1;

}

/**

* Finds the aliquot sum of an integer number

* @param number a positive integer

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

public static int aliquotSum(int number) {

int sum = 0;

for (int i = 1, limit = number / 2; i <= limit; ++i) {

if (number % i == 0) {

sum += i;

}

return sum;

}

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