docs: add time & space complexity for Stacks (#7132)"

Author: Srikar-Yekabote

src/main/java/com/thealgorithms/stacks/BalancedBrackets.java

@@ -23,17 +23,17 @@ private BalancedBrackets() {
     /**
      * Check if {@code leftBracket} and {@code rightBracket} is paired or not
      *
-     * @param leftBracket left bracket
+     * @param leftBracket  left bracket
      * @param rightBracket right bracket
      * @return {@code true} if {@code leftBracket} and {@code rightBracket} is
-     * paired, otherwise {@code false}
+     *         paired, otherwise {@code false}
      */
     public static boolean isPaired(char leftBracket, char rightBracket) {
         char[][] pairedBrackets = {
-            {'(', ')'},
-            {'[', ']'},
-            {'{', '}'},
-            {'<', '>'},
+                { '(', ')' },
+                { '[', ']' },
+                { '{', '}' },
+                { '<', '>' },
         };
         for (char[] pairedBracket : pairedBrackets) {
             if (pairedBracket[0] == leftBracket && pairedBracket[1] == rightBracket) {
@@ -48,7 +48,7 @@ public static boolean isPaired(char leftBracket, char rightBracket) {
      *
      * @param brackets the brackets
      * @return {@code true} if {@code brackets} is balanced, otherwise
-     * {@code false}
+     *         {@code false}
      */
     public static boolean isBalanced(String brackets) {
         if (brackets == null) {
@@ -57,24 +57,34 @@ public static boolean isBalanced(String brackets) {
         Stack<Character> bracketsStack = new Stack<>();
         for (char bracket : brackets.toCharArray()) {
             switch (bracket) {
-            case '(':
-            case '[':
-            case '<':
-            case '{':
-                bracketsStack.push(bracket);
-                break;
-            case ')':
-            case ']':
-            case '>':
-            case '}':
-                if (bracketsStack.isEmpty() || !isPaired(bracketsStack.pop(), bracket)) {
+                case '(':
+                case '[':
+                case '<':
+                case '{':
+                    bracketsStack.push(bracket);
+                    break;
+                case ')':
+                case ']':
+                case '>':
+                case '}':
+                    if (bracketsStack.isEmpty() || !isPaired(bracketsStack.pop(), bracket)) {
+                        return false;
+                    }
+                    break;
+                default:
                     return false;
-                }
-                break;
-            default:
-                return false;
             }
         }
         return bracketsStack.isEmpty();
     }
 }
+/**
+ * Time Complexity: O(n)
+ * Space Complexity: O(n)
+ * 
+ * reasons:
+ * 1. The time complexity of the isBalanced method is O(n), where n is the
+ * length of the input string.
+ * 2. The space complexity of the isBalanced method is O(n), where n is the
+ * length of the input string.
+ */