Sum of k-Mirror Numbers
A k-mirror number is a positive integer without leading zeros that reads the same both forward and backward in base-10 as well as in base-k.
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For example,
9is a 2-mirror number. The representation of9in base-10 and base-2 are9and1001respectively, which read the same both forward and backward. -
On the contrary,
4is not a 2-mirror number. The representation of4in base-2 is100, which does not read the same both forward and backward.
Provided the base k and the number n, produce the sum of the n smallest k-mirror numbers.
Input: k = 2, n = 5
Output: 25
Explanation: The 5 smallest 2-mirror numbers and their representations in base-2 are listed as follows:
| base-10 | base-2 |
|---|---|
| 1 | 1 |
| 3 | 11 |
| 5 | 101 |
| 7 | 111 |
| 9 | 1001 |
Their sum = 1 + 3 + 5 + 7 + 9 = 25.
Input: k = 3, n = 7
Output: 499
Explanation: The 7 smallest 3-mirror numbers are and their representations in base-3 are listed as follows:
| base-10 | base-3 |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 4 | 11 |
| 8 | 22 |
| 121 | 11111 |
| 151 | 12121 |
| 212 | 21212 |
Their sum = 1 + 2 + 4 + 8 + 121 + 151 + 212 = 499.
Input: k = 7, n = 17
Output: 20379000
Explanation: The 17 smallest 7-mirror numbers are:
1, 2, 3, 4, 5, 6, 8, 121, 171, 242, 292, 16561, 65656, 2137312, 4602064, 6597956, 6958596
Constraints
2 <= k <= 91 <= n <= 30
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