using System;

using System.Collections.Generic;

​

    public class Program

    {

        static Boolean Matching(char character1,char character2)

        {

            if(character1 == '(' && character2 == ')')

            {

                return true;

            }

            else if(character1 == '{' && character2 == '}')

            {

                return true;

            }else if(character1 == '{' && character2 == '}')

            {

                return true;

            }

            return false;

        }

        static Boolean Bracket(char[] exp)

        {

            Stack<char> st = new Stack<char>();

            for (int i = 0; i < exp.Length; i++)

            {

                if (exp[i] == '{' || exp[i] == '(' || exp[i] == '[')

                {

                    st.Push(exp[i]);

                }

                if(exp[i] == ')' || exp[i] == '}' || exp[i] == ']')

                {

                   if(st.Count == 0)

                    {

                        return false;

                    }else if (!Matching(st.Pop(), exp[i]))

                    {

                        return false;

                    }

                }

            }

            return false;

        }

        public void Main(string[] args)

        {

            // char[] exp = '{()}' is a correct string

            //'{(}' is an incorrect string

            //'[()()]' is a correct string

            char[] a = {'{','(',')','}'};

            char[] b = {'{','(','}'};

            char[] c = { '[','(',')','(',')',']'};

            if (!Bracket(a))

            {

                Console.WriteLine("{()} : IS correct string");

            }

              if (!Bracket(b))

            {

                Console.WriteLine("{(} : Not correct string");

            }

              if (!Bracket(c))

            {

                Console.WriteLine("[()()] : IS correct string");

            }

        }

    }

​

​