comefrom: <awangdev>921. Minimum Add to Make Parentheses Valid_1.java
code: public int minAddToMakeValid(String s) {
          if (s == null || s.length() == 0) {
              return 0;
          }
          Stack<Character> stack = new Stack<>();
          int count = 0;
          for (char c : s.toCharArray()) {
              if (c == '(') stack.push(c);
              else if (stack.isEmpty()) count++;
              else stack.pop();
          }
          return count + stack.size();
      }
masked: public int sample_funcname ( String var_0 ) {
    if ( var_0 == null || var_0 . length ( ) == 0 ) {
      return 0 ;
    }
    Stack < Character > var_1 = new Stack < > ( ) ;
    int var_2 = 0 ;
    for ( char var_3 : var_0 . toCharArray ( ) ) {
      if ( var_3 == '(' ) var_1 . push ( var_3 ) ;
      else if ( var_1 . isEmpty ( ) ) var_2 ++ ;
      else var_1 . pop ( ) ;
    }
    return var_2 + var_1 . size ( ) ;
  }
  