3120. Count the Number of Special Characters I

/**
 * Problem: LeetCode 3120 - Count the Number of Special Characters I
 * Difficulty: Easy
 * Language: Java
 * Author: CodeByTushu
 */
class Solution {
    public int numberOfSpecialChars(String word) {
        int lowerMask = 0;
        int upperMask = 0;

        for (int i = 0; i < word.length(); i++) {
            char ch = word.charAt(i);
            if (ch >= 'a' && ch <= 'z') {
                lowerMask |= (1 << (ch - 'a'));
            } else if (ch >= 'A' && ch <= 'Z') {
                upperMask |= (1 << (ch - 'A'));
            }
        }

        return Integer.bitCount(lowerMask & upperMask);
    }
}

"""
Problem: LeetCode 3120 - Count the Number of Special Characters I
Difficulty: Easy
Language: Python
Author: CodeByTushu
"""
class Solution:
    def numberOfSpecialChars(self, word: str) -> int:
        lower_mask = 0
        upper_mask = 0

        for ch in word:
            if 'a' <= ch <= 'z':
                lower_mask |= (1 << (ord(ch) - ord('a')))
            elif 'A' <= ch <= 'Z':
                upper_mask |= (1 << (ord(ch) - ord('A')))

        return (lower_mask & upper_mask).bit_count()

/**
 * Problem: LeetCode 3120 - Count the Number of Special Characters I
 * Difficulty: Easy
 * Language: C++
 * Author: CodeByTushu
 */
#include <string>

using namespace std;

class Solution {
public:
    int numberOfSpecialChars(string word) {
        int lowerMask = 0;
        int upperMask = 0;

        for (char ch : word) {
            if (ch >= 'a' && ch <= 'z') {
                lowerMask |= (1 << (ch - 'a'));
            } else if (ch >= 'A' && ch <= 'Z') {
                upperMask |= (1 << (ch - 'A'));
            }
        }

        return __builtin_popcount(lowerMask & upperMask);
    }
};

/**
 * Problem: LeetCode 3120 - Count the Number of Special Characters I
 * Difficulty: Easy
 * Language: JavaScript
 * Author: CodeByTushu
 */
/**
 * @param {string} word
 * @return {number}
 */
var numberOfSpecialChars = function(word) {
    let lowerMask = 0;
    let upperMask = 0;

    for (let i = 0; i < word.length; i++) {
        const code = word.charCodeAt(i);
        if (code >= 97 && code <= 122) { // 'a' - 'z'
            lowerMask |= (1 << (code - 97));
        } else if (code >= 65 && code <= 90) { // 'A' - 'Z'
            upperMask |= (1 << (code - 65));
        }
    }

    let common = lowerMask & upperMask;
    let count = 0;
    while (common > 0) {
        common &= (common - 1);
        count++;
    }
    return count;
};