Create 2299-strong-password-checker-ii.java

Author: sanajitjana

Easy/2299-strong-password-checker-ii.java

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+/**
+ * LeetCode Problem: 2299. Strong Password Checker II
+ * Link: https://leetcode.com/problems/strong-password-checker-ii/
+ *
+ * Description:
+ * A password is said to be strong if:
+ * - It has at least 8 characters.
+ * - It contains at least one lowercase letter.
+ * - It contains at least one uppercase letter.
+ * - It contains at least one digit.
+ * - It contains at least one special character from the string "!@#$%^&*()-+".
+ * - It does not contain two identical characters in adjacent positions.
+ *
+ * Given a string password, return true if it is a strong password. Otherwise, return false.
+ *
+ * ------------------------------------------------------------------------
+ * Time Complexity: O(n)  // iterate through the string once
+ * Space Complexity: O(1) // only a few boolean flags used
+ * ------------------------------------------------------------------------
+ */
+
+class Solution {
+    public boolean strongPasswordCheckerII(String password) {
+        if (password.length() < 8) return false;
+
+        boolean lower = false, upper = false, digit = false, special = false;
+        String specials = "!@#$%^&*()-+";
+
+        for (int i = 0; i < password.length(); i++) {
+            char c = password.charAt(i);
+
+            if (Character.isLowerCase(c)) lower = true;
+            else if (Character.isUpperCase(c)) upper = true;
+            else if (Character.isDigit(c)) digit = true;
+            else if (specials.indexOf(c) >= 0) special = true;
+
+            // check adjacent characters
+            if (i > 0 && c == password.charAt(i - 1)) return false;
+        }
+
+        return lower && upper && digit && special;
+    }
+}