ConstitutiveNumbers | Topcoder Archive

Problem Statement

Let's call a number constitutive if it can be expressed as a sum of three or more successive positive integers. For example, 14 is a constitutive number because 14 = 2+3+4+5, but 13 is not a constitutive number.

You will be given two ints A and B. Return the number of constitutive numbers between A and B, inclusive.

Definition

Class:: ConstitutiveNumbers
Method:: count
Parameters:: int, int
Returns:: int
Method signature:: int count(int A, int B)
(be sure your method is public)

Constraints

A will be between 1 and 1,000,000,000, inclusive.
B will be between A and A + 1000, inclusive.

Examples

```
1
```
```
15
```
```
Returns: 6
```
The first 6 constitutive numbers are: 6 = 1 + 2 + 3 9 = 2 + 3 + 4 10 = 1 + 2 + 3 + 4 12 = 3 + 4 + 5 14 = 2 + 3 + 4 + 5 15 = 4 + 5 + 6
```
1
```
```
101
```
```
Returns: 69
```
```
1000
```
```
1030
```
```
Returns: 26
```
```
7245723
```
```
7246428
```
```
Returns: 657
```
```
1000000000
```
```
1000001000
```
```
Returns: 952
```

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