Here is the general goal of this exercise:

For each string, print whether or not the string of brackets is balanced on a new line. If the brackets are balanced, print YES; otherwise, print NO.

Please comment as this was a job interview and I had 30 mins to give something working and the best performance wise.

using System; using System.Collections.Generic; using System.Linq; using Microsoft.VisualStudio.TestTools.UnitTesting;  namespace JobInterviewTests {     [TestClass]     public class UnitTest1     {         [TestMethod]         public void TestMethod1()         {              List<string> list = new List<string> {"({[]})", "][(]}})("};              foreach (var barcketsList in list)              {                 string expression = barcketsList;                 Stack<char> stack = new Stack<char>();                 char[] symbols = expression.ToCharArray();                 if (symbols.Length == 0)                 {                        break;                 }                 bool flagPrint = false;                 for (int start = 0; start < symbols.Count(); start++)                 {                     char temp = symbols[start];                     if (temp == '[' || temp == '{' || temp == '(')                     {                         stack.Push(temp);                     }                     else                     {                         if (stack.Count == 0) //only closer no opening                         {                             Console.WriteLine("NO");                             flagPrint = true;                             break;                          }                         char top = stack.Peek();                         if (temp == ']')                         {                             if (top != '[')                             {                                    break;                             }                             stack.Pop();                         }                         else if (temp == '}')                         {                             if (top != '{')                             {                                  break;                             }                             stack.Pop();                         }                         else // temp == ')'                         {                             if (top != '(')                             {                                  break;                             }                             stack.Pop();                         }                     }                 }                 if (!stack.Any() && !flagPrint)                 {                     Console.WriteLine("YES");                 }                 else if (!flagPrint)                 {                     Console.WriteLine("NO");                 }             }         }     } }