3120. Count the Number of Special Characters I

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3120. Count the Number of Special Characters I

Description

You are given a string word. A letter is called special if it appears both in lowercase and uppercase in word.

Return the number of special letters in word.

Example 1:

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Input: word = "aaAbcBC"

Output: 3

Explanation:

The special characters in `word` are `'a'`, `'b'`, and `'c'`.

Example 2:

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Input: word = "abc"

Output: 0

Explanation:

No character in `word` appears in uppercase.

Example 3:

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Input: word = "abBCab"

Output: 1

Explanation:

The only special character in `word` is `'b'`.

Constraints:

  • 1 <= word.length <= 50
  • word consists of only lowercase and uppercase English letters.

Hints/Notes

  • N/A

Solution

Language: C++

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class Solution {
public:
    int numberOfSpecialChars(string word) {
        set<int> s;
        for (char c : word) {
            s.insert(c - 'A');
        }
        int res = 0;
        for (int i = 0; i < 26; i++) {
            if (s.contains(i) && s.contains(i + 'a' - 'A')) {
                res++;
            }
        }
        return res;
    }
};