leetcode-algorithms/src/HappyNumber.java at master · anishLearnsToCode/leetcode-algorithms · GitHub

29 lines (26 loc) · 769 Bytes

import java.util.HashSet;

import java.util.Set;

public class HappyNumber {

public static boolean isHappy(int number) {

return isHappy(number, new HashSet<>());

}

private static boolean isHappy(long number, Set<Long> sum) {

long sumSquaresDigits = sumDigitSquares(number);

if (sumSquaresDigits == 1) {

return true;

}

if (sum.contains(sumSquaresDigits)) {

return false;

}

sum.add(sumSquaresDigits);

return isHappy(sumSquaresDigits, sum);

}

private static long sumDigitSquares(long number) {

long result = 0;

while (number > 0) {

result += Math.pow(number % 10, 2);

number /= 10;

}

return result;

}

Expand file tree