NoSumOrProd | Topcoder Archive

Problem Statement

Return an integer, I, that appears in a given int[] and satifies the following requirements. If more than one element satisfies the requirements, your method should return the element satisfying the requirements which appears first in the int[].
* The sum of no two other integers in the list equals I.
* The product of no two other integers in the list equals I.
If no such integer exists, return -1.

Definition

Class:: NoSumOrProd
Method:: getFirst
Parameters:: int[]
Returns:: int
Method signature:: int getFirst(int[] numbers)
(be sure your method is public)

Notes

When determining if numbers[a] and numbers[b] add or multiply to numbers[c], a, b, and c must be different.

Constraints

numbers contains between 3 and 50 ints, inclusive.
Elements of numbers are between -1000 and 1000, inclusive.

Examples

```
{1, 2, 3}
```
```
Returns: 1
```
```
{3, 2, 1} 
```
```
Returns: 2
```
By the first note, 1 + 1 cannot be used.
```
{20, -30, 10, 10, -15, -15, 0}
```
```
Returns: 0
```
Note 10 + 10 = 20 and -15 + -15 = -30 invalidate 20 and -30 because there are two 10's and two -15's.
```
{20, -30, 10, 10, -15, -15, 0, 0}
```
```
Returns: -1
```
0 cannot be returned because 0 times any other number is 0
```
{0, 0, 0, 0}
```
```
Returns: -1
```
```
{3, 4, 5, 35, 3, 0}
```
```
Returns: 4
```
Note 4, 5, 35 and 0 all satisfy the properties, but 4 appears first in the int[] so it is the returned value.

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