Problem Statement
An integer arithmetic progression is a sequence defined by two positive integers, p and q, where p is the first element in the sequence, and all other elements are obtained by adding q to the previous element. For example, if p = 1 and q = 2, the sequence would be: 1, 3, 5, 7, ...
An integer geometric progression is a sequence defined by two positive integers, p and q, where p is the first element in the sequence, and all other elements are obtained by multiplying the previous element by q. For example, if p = 3 and q = 2, the sequence would be: 3, 6, 12, ...
You are given a int[] A, which contains either an integer arithmetic or geometric progression. Determine which one it is and return the next element in the sequence. It is guaranteed that A will uniquely represent either an arithmetic or geometric progression and that result will fit in a 32-bit signed integer.
Definition
- Class:
- GuessingNextElement
- Method:
- guess
- Parameters:
- int[]
- Returns:
- int
- Method signature:
- int guess(int[] A)
- (be sure your method is public)
Constraints
- A will contain between 3 and 50 elements, inclusive.
- Each element of A will be between 1 and 10^6, inclusive.
- A will be sorted in ascending order.
- A will uniquely represent either an arithmetic or geometric progression.
Examples
{364,843,1322,1801}Returns: 2280
This sequence represents an arithmetic progression where p = 364 and q = 479. The next element is 1801 + 479 = 2280.{394,1172,1950,2728,3506,4284,5062,5840}Returns: 6618
{13,117,1053,9477,85293}Returns: 767637
This sequence represents a geometric progression where p = 13 and q = 9. The next element is 85293 * 9 = 76737.{22,220,2200,22000}Returns: 220000
{250000, 500000, 1000000}Returns: 2000000
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