d be valid string test2 = "{[}]"; // Should be invalid string test3 = "(]"; // Should be invalid cout << "Test 1: " << sol.isValid(test1) << endl; cout << "Test 2: " << sol.isValid(test2) << endl; cout << "Test 3: " << sol.isValid(test3) << endl; return 0; } 2a:T75d,using System; using System.Collections.Generic; public class Solution { public bool isValid(string s) { // Creating a stack to keep track of opening parentheses Stack stack = new Stack(); // Iterating through each character in the input string foreach (char c in s) { // If the character is an opening parenthesis, push it onto the stack if (c == '(' || c == '{' || c == '[') { stack.Push(c); } else { // If stack is empty and we have a closing parenthesis, the string is not balanced if (stack.Count == 0) { return false; } // Pop the top character from the stack char top = stack.Pop(); // If the character is a closing parenthesis, check whether // it corresponds to the most recent opening parenthesis if (c == ')' && top != '(') { return false; } if (c == '}' && top != '{') { return false; } if (c == ']' && top != '[') { return false; } } } // If the stack is empty, all opening parentheses had a corresponding closing match return stack.Count == 0; } public static void Main(string[] args) { Solution bp = new Solution(); // Test cases to verify the solution string test1 = "{[()]}"; string test2 = "{[}]"; string test3 = "(]"; Console.WriteLine("Test 1: " + bp.isValid(