Test Case Pass: 51/54

blog_deepseek_r1_coding_leetcode_question_response.cpp

class Solution {
public:
    int strongPasswordChecker(string password) {
        int n = password.size();
        
        // Check for missing character types
        bool has_lower = false, has_upper = false, has_digit = false;
        for (char c : password) {
            if (islower(c)) has_lower = true;
            else if (isupper(c)) has_upper = true;
            else if (isdigit(c)) has_digit = true;
        }
        int missing = 3 - (has_lower + has_upper + has_digit);
        
        // Check for repeating sequences and calculate initial required_repeats
        vector<int> repeat_counts;
        int required_repeats = 0;
        int i = 0;
        while (i < n) {
            int j = i;
            while (j < n && password[j] == password[i]) ++j;
            int len = j - i;
            if (len >= 3) {
                repeat_counts.push_back(len);
                required_repeats += len / 3;
            }
            i = j;
        }
        
        if (n < 6) {
            return max(6 - n, missing + required_repeats);
        } else if (n <= 20) {
            return max(missing, required_repeats);
        } else { // n > 20
            int over = n - 20;
            int delete_ops = over;
            
            // Categorize repeats by their mod 3 value
            int r0 = 0, r1 = 0, r2 = 0;
            for (int l : repeat_counts) {
                int mod = l % 3;
                if (mod == 0) r0++;
                else if (mod == 1) r1++;
                else r2++;
            }
            
            // Apply deletions to reduce required_repeats optimally
            int use;
            use = min(r0, over);
            required_repeats -= use;
            over -= use;
            
            use = min(r1, over / 2);
            required_repeats -= use;
            over -= use * 2;
            
            use = over / 3;
            required_repeats -= use;
            over -= use * 3;
            
            required_repeats = max(required_repeats, 0);
            
            return delete_ops + max(missing, required_repeats);
        }
    }
};

Problem Link: https://leetcode.com/problems/strong-password-checker