BitFlips | Topcoder Archive

Problem Statement

Your company builds 20-bit binary counters for industrial applications. You want to test how many bits get changed while incrementing through a particular range. For example, lets say you were incrementing from 1 to 6. The sequence of numbers in binary would be (only 4 low order bits shown for clarity):

0001->0010->0011->0100->0101->0110

From 1 to 2 two bits were changed. From 2 to 3 one bit was changed. From 3 to 4 three bits were changed. Adding up the changes at each increment from 1 to 6, 9 total bits changed. Given low, the number to begin from, and high the number to end at, return the total number of bits changed during the incrementing process.

Definition

Class:: BitFlips
Method:: howMany
Parameters:: int, int
Returns:: int
Method signature:: int howMany(int low, int high)
(be sure your method is public)

Constraints

low will be between 0 and 99999 inclusive
high will be between 0 and 100000 inclusive
low will be less than high

Examples

```
1
```
```
6
```
```
Returns: 9
```
Example from above
```
1
```
```
100000
```
```
Returns: 199993
```
As big as it gets
```
50
```
```
51
```
```
Returns: 1
```
```
65535
```
```
65536
```
```
Returns: 17
```
```
99
```
```
9999
```
```
Returns: 19796
```

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