C# Code - Runtime: 88ms - Beating 94.54%

anirudh.arya

  public class Solution
    {
        public bool IsValid(string s)
        {
            bool valid = true;

            Stack k = new Stack();
            char[] c = s.ToCharArray();

            for (int i = 0; i < s.Length; i++)
            {
                if (c[i] == '(' || c[i] == '{' || c[i] == '[')
                {
                    k.Push(c[i]);
                }
                else
                {
                    if(k.Count ==0)
                    {
                        valid = false; break;
                    }
                    else
                    {
                        if (k.Peek() is null)
                        {
                            valid = false; break;
                        }
                        else
                        {
                            char l = char.Parse(k.Pop().ToString());
                            if ((GetC(l) == 'o' || GetC(l) != c[i]))
                            {
                                valid = false; break;
                            }
                        }
                    }
                    
                }
            }
            if (k.Count != 0) valid = false;
            return valid;
        }

        public char GetC(char l)
        {
            if (l == '[')
                return ']';
            if (l == '(')
                return ')';
            if (l == '{')
                return '}';
            else
                return 'o';
        }
    }