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程式語言 - LeetCode - C++ - 3121. Count the Number of Special Characters II

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題目：


解答：

class Solution {
public:
    int numberOfSpecialChars(string word) {
        unordered_map<char, int> lower;
        unordered_map<char, int> upper;

        for (int i = 0; i < word.size(); ++i) {
            char c = word[i];

            if (islower(c)) {
                lower[c] = i;
            }
            else if (upper.count(c) == 0) {
                upper[c] = i;
            }
        }

        int ans = 0;

        for (auto [k, v] : lower) {
            char c = toupper(k);
        
            if (upper.count(c) && upper[c] > v) {
                ans += 1;
            }
        }

        return ans;
    }
};