comefrom: <awangdev>Missing Number_1.java
code: private void swap(int[] nums, int x, int y) {
  
          int temp = nums[x];
          nums[x] = nums[y];
          nums[y] = temp;
      }
masked: private void var_0 ( int [ ] var_1 , int var_2 , int var_3 ) {
    int var_4 = var_1 [ var_2 ] ;
    var_1 [ var_2 ] = var_1 [ var_3 ] ;
    var_1 [ var_3 ] = var_4 ;
  }
  