Sum of k-Mirror Numbers - Practice Coding | SlaveCode
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2081. Sum of k-Mirror Numbers
Hard
50 Points
Math
Enumeration
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.
Given the base k and the number n, return the sum of the n smallest k-mirror numbers.
Examples
Example 1
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.
Example 2
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.
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.
Given the base k and the number n, return the sum of the n smallest k-mirror numbers.
Examples
Example 1
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.
Example 2
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.