762. Prime Number of Set Bits in Binary Representation

/**
 * Problem: LeetCode 762 - Prime Number of Set Bits in Binary Representation
 * Difficulty: Easy
 * Language: Java
 * Author: CodeByTushu
 */
class Solution {
    public int countPrimeSetBits(int left, int right) {
        // Bitmask representing prime bit counts up to 19:
        // Primes <= 19 are 2, 3, 5, 7, 11, 13, 17, 19
        // mask = (1<<2)|(1<<3)|(1<<5)|(1<<7)|(1<<11)|(1<<13)|(1<<17)|(1<<19) = 665772
        int primeMask = 665772;
        int count = 0;

        for (int i = left; i <= right; i++) {
            int setBits = Integer.bitCount(i);
            if (((primeMask >> setBits) & 1) != 0) {
                count++;
            }
        }

        return count;
    }
}

"""
Problem: LeetCode 762 - Prime Number of Set Bits in Binary Representation
Difficulty: Easy
Language: Python
Author: CodeByTushu
"""
class Solution:
    def countPrimeSetBits(self, left: int, right: int) -> int:
        # Primes <= 19: 2, 3, 5, 7, 11, 13, 17, 19
        prime_mask = 665772
        count = 0

        for num in range(left, right + 1):
            set_bits = num.bit_count()
            if (prime_mask >> set_bits) & 1:
                count += 1

        return count

/**
 * Problem: LeetCode 762 - Prime Number of Set Bits in Binary Representation
 * Difficulty: Easy
 * Language: C++
 * Author: CodeByTushu
 */
#include <algorithm>

class Solution {
public:
    int countPrimeSetBits(int left, int right) {
        // Primes <= 19: 2, 3, 5, 7, 11, 13, 17, 19
        const int primeMask = 665772;
        int count = 0;

        for (int i = left; i <= right; i++) {
            int setBits = __builtin_popcount(i);
            if ((primeMask >> setBits) & 1) {
                count++;
            }
        }

        return count;
    }
};

/**
 * Problem: LeetCode 762 - Prime Number of Set Bits in Binary Representation
 * Difficulty: Easy
 * Language: JavaScript
 * Author: CodeByTushu
 */
/**
 * @param {number} left
 * @param {number} right
 * @return {number}
 */
var countPrimeSetBits = function(left, right) {
    const primeMask = 665772;
    let count = 0;

    for (let i = left; i <= right; i++) {
        let n = i;
        let setBits = 0;
        while (n > 0) {
            n &= (n - 1);
            setBits++;
        }

        if ((primeMask >> setBits) & 1) {
            count++;
        }
    }

    return count;
};