comefrom: <awangdev>850. Rectangle Area II_1.java
code: private int calcHeightDiff(TreeMap<Integer, Integer> map) {
  
          int height = 0, pre = 0, count = 0;
          for (Map.Entry<Integer, Integer> e : map.entrySet()) {
              if (count > 0) height += e.getKey() - pre;
              count += e.getValue();
              pre = e.getKey();
          }
          return height;
      }
masked: private int sample_funcname ( TreeMap < Integer , Integer > var_2 ) {
    int var_4 = 0 , var_5 = 0 , var_6 = 0 ;
    for ( Map . Entry < Integer , Integer > var_8 : var_2 . entrySet ( ) ) {
      if ( var_6 > 0 ) var_4 += var_8 . getKey ( ) - var_5 ;
      var_6 += var_8 . getValue ( ) ;
      var_5 = var_8 . getKey ( ) ;
    }
    return var_4 ;
  }
  