comefrom: <qiyuangong>215_Kth_Largest_Element_in_an_Array_1.java
code: private void exch(int[] a, int i, int j) {
          final int tmp = a[i];
          a[i] = a[j];
          a[j] = tmp;
      }
masked: private void var_0 ( int [ ] var_1 , int var_2 , int var_3 ) {
    final int var_4 = var_1 [ var_2 ] ;
    var_1 [ var_2 ] = var_1 [ var_3 ] ;
    var_1 [ var_3 ] = var_4 ;
  }
  