main.dart

int? parseIntPrefix(String s) {
  var re = RegExp(r'(-?[0-9]+).*');
  var match = re.firstMatch(s);
  if (match == null) {
    return null;
  }
  return int.parse(match.group(1)!);
}

int compareIntPrefixes(String a, String b) {
  var aValue = parseIntPrefix(a);
  var bValue = parseIntPrefix(b);
  if (aValue != null && bValue != null) {
    return aValue - bValue;
  }

  if (aValue == null && bValue == null) {
    // If neither string has an integer prefix, sort the strings lexically.
    return a.compareTo(b);
  }

  // Sort strings with integer prefixes before strings without.
  if (aValue == null) {
    return 1;
  } else {
    return -1;
  }
}

void main() {
  List<String> hi = ['1','3c','2','1c','3a','bca','a','11','2','3','4','7','5','6'];
  hi.sort();
  print(hi);
  hi.sort(compareIntPrefixes);
  print(hi);
   hi.sort();
  print(hi);
}