Valid Parentheses

Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

An input string is valid if:

Open brackets must be closed by the same type of brackets. Open brackets must be closed in the correct order. Every close bracket has a corresponding open bracket of the same type.

Example 1:

Input: s = "()" Output: true Example 2:

Input: s = "()[]{}" Output: true Example 3:

Input: s = "(]" Output: false

Constraints:

1 <= s.length <= 104 s consists of parentheses only '()[]{}'.

Approach 1: we will replace a set the parentheses from the string until every possible pair. then if something is left in the string return false else return true; Code:

using System;
using System.Collections;

namespace ValidParentheses
{
    class Program
    {
        public bool IsValid(string s)
        {
            int n = 0;
            while (s.Length != n)
            {
                n = s.Length;
                s = s.Replace("()", "");
                s = s.Replace("{}", "");
                s = s.Replace("[]", "");

            }
            return s.Length == 0;
        }


        static void Main(string[] args)
        {
            string s = "()";
            Program obj = new Program();
            bool k = obj.IsValid(s);
        }
    }
}