34 lines
1.0 KiB
Java
34 lines
1.0 KiB
Java
package Maths;
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/**
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* In number theory, a perfect number is a positive integer that is equal to the sum of
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* its positive divisors, excluding the number itself. For instance, 6 has divisors 1, 2 and 3
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* (excluding itself), and 1 + 2 + 3 = 6, so 6 is a perfect number.
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* <p>
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* link:https://en.wikipedia.org/wiki/Perfect_number
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* </p>
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*/
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public class PerfectNumber {
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public static void main(String[] args) {
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assert isPerfectNumber(6); /* 1 + 2 + 3 == 6 */
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assert !isPerfectNumber(8); /* 1 + 2 + 4 != 8 */
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assert isPerfectNumber(28); /* 1 + 2 + 4 + 7 + 14 == 28 */
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}
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/**
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* Check if {@code number} is perfect number or not
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*
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* @param number the number
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* @return {@code true} if {@code number} is perfect number, otherwise false
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*/
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public static boolean isPerfectNumber(int number) {
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int sum = 0; /* sum of its positive divisors */
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for (int i = 1; i < number; ++i) {
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if (number % i == 0) {
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sum += i;
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}
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}
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return sum == number;
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}
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}
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