Problem Statement |
| | A number is called a perfect power if it can be written in the form m^k, where m and k are positive integers, and k > 1.
Given two positive integers A and B, find the two perfect powers between A and B, inclusive, that are closest to each other, and return the absolute difference between them. If less than two perfect powers exist in the interval, return -1 instead. |
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Definition |
| | | Class: | PerfectPowers | | Method: | nearestCouple | | Parameters: | long, long | | Returns: | long | | Method signature: | long nearestCouple(long A, long B) | | (be sure your method is public) |
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Notes |
| - | 1 is a perfect power. |
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Constraints |
| - | A will be between 1 and 10^18, inclusive. |
| - | B will be between A+1 and 10^18, inclusive. |
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Examples |
| 0) | |
| | | Returns: 3 | | 1 and 4 are the first pair of perfect powers. |
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| 1) | |
| | | Returns: 1 | | 8 and 9 are the closest pair of perfect powers. |
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| 2) | |
| | | Returns: -1 | | No pair of perfect powers is present in the interval. |
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| 3) | |
| | | Returns: 1 | | This is the largest possible range, and 8 and 9 are the closest pair of perfect powers. |
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| 4) | |
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