adjacent duplicates. The suggestion fixes all issues.

Example 3

Input: password = "IloveK5kc!"
Output: "IloveK5kc!"
Explanation: The password is already strong.

Method 1 – Greedy Validation and Minimal Fixes

Intuition

The key idea is to check for all required password properties (length, lowercase, uppercase, digit, special character, no adjacent duplicates). If any property is missing, we add or modify characters as needed, always making the minimal change. For suggestions, we fix missing types, break up adjacent duplicates, and pad the password to the required length.

Approach

Check if the password meets all criteria:
- At least 8 characters.
- At least one lowercase, one uppercase, one digit, one special character.
- No two identical adjacent characters.
If strong, return the password as is.
Otherwise:
- Insert missing character types at the earliest opportunity.
- Break up adjacent duplicates by inserting a non-duplicate character.
- If the password is too short, append random valid characters to reach length 8.
- Ensure all fixes are minimal and the result is strong.

Code

[{"language":"C++","code":"class Solution {\npublic:\n  std::string suggestStrongPassword(std::string password) {\n    std::string specials = \"!@#$%^&*()-+\";\n    bool hasLower = false, hasUpper = false, hasDigit = false, hasSpecial = false;\n    for (char c : password) {\n      if (islower(c)) hasLower = true;\n      else if (isupper(c)) hasUpper = true;\n      else if (isdigit(c)) hasDigit = true;\n      else if (specials.find(c) != std::string::npos) hasSpecial = true;\n    }\n    std::string ans = password;\n    if (!hasLower) ans += 'a';\n    if (!hasUpper) ans += 'A';\n    if (!hasDigit) ans += '1';\n    if (!hasSpecial) ans += '!';\n    // Break adjacent duplicates\n    for (int i = 1; i < (int)ans.size(); ++i) {\n      if (ans[i] == ans[i-1]) {\n        ans.insert(ans.begin() + i, (ans[i] == 'a' ? 'B' : 'a'));\n        ++i;\n      }\n    }\n    while ((int)ans.size() < 8) ans += 'x';\n    if ((int)ans.size() > 100) ans = ans.substr(0, 100);\n    return ans;\n  }\n};","lang":"cpp","html":"<pre class=\"shiki shiki-themes github-light github-dark\"

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