comefrom: <awangdev>689. Maximum Sum of 3 Non-Overlapping Subarrays_3.java
code: private int[] calcPresum(int[] nums) {
  
          int[] presum = new int[nums.length + 1];
          for (int i = 1; i <= nums.length; i++) 
              presum[i] += presum[i - 1] + nums[i - 1];
          return presum;
      }
masked: private int [ ] sample_funcname ( int [ ] var_0 ) {
    int [ ] var_1 = new int [ var_0 . length + 1 ] ;
    for ( int var_2 = 1 ;
    var_2 <= var_0 . length ;
    var_2 ++ ) var_1 [ var_2 ] += var_1 [ var_2 - 1 ] + var_0 [ var_2 - 1 ] ;
    return var_1 ;
  }
  