Brackets balance codility.cs

  class Program
    {
        static void Main(string[] args)
        {
            //Console.WriteLine(Convert.ToString(1000));
            Console.WriteLine(solution(")("));
            Console.WriteLine(solution("{[()()]}"));
            Console.WriteLine(solution("([)()]"));
        }
        public static int solution(string S)
        {
            if (string.IsNullOrEmpty(S))
                return 1;
            var dicConst = new Dictionary<string, string>
            {
                {"{", "}"},
                {"(", ")"},
                {"[", "]"},
            };
            var final = new Stack<string>();
            foreach (var chCh in S)
            {
                string ch = char.ToString(chCh);
                var key = dicConst.FirstOrDefault(d => d.Value == ch).Key;
                if(!string.IsNullOrEmpty(key) && final.Count>0 &&final.Peek() == key)
                    final.Pop();
                 else
                    final.Push(ch);
            }
            return final.Count > 0? 0 : 1;
        }
    }