Stopwatch stopwatch = new Stopwatch()..start();
doSomething();
print('doSomething() executed in ${stopwatch.elapsed}');

bool validBraces(String str) {
  var prev = "";
  while (str.length != prev.length) {
            prev = str;
            str = str
                .replaceAll("()", "")
                .replaceAll("[]", "")
                .replaceAll("{}", "");                
    }
    return (str.length == 0);
}

bool validBraces(String braces) {
    Stopwatch stopwatch = new Stopwatch()..start();
    // TODO
    bool result = true;
    List<String> currentCloser = [];
    for(int i=0; i < braces.length; i++){
      String currentCloserChar = currentCloser.isEmpty ? "" : currentCloser.last;
      //print("current Closer - braches i => $currentCloserChar - ${braces[i]}");
      // အခု ပိတ်မှာလား?
      if( currentCloserChar != braces[i]){
        result = false;

        // အသစ် ထပ်လာမှာလား
        switch (braces[i]){
          case "(":
            currentCloser.add(")");
            break;
          case "{":
            currentCloser.add("}");
            break;
          case "[":
            currentCloser.add("]");
            break;
          default:
            // အသစ်လည်း ထပ်လာမှာ မဟုတ်ဘူး၊ စပြီး တလွဲကြီး ဖြစ်နေပြီ
            currentCloser.add("-");
        }
      }
      else{
        result = true;
        currentCloser.removeLast();
      }

      //print("result is $result");

    }
    print('validBraces executed in ${stopwatch.elapsed}');
    return result;
  }