Identity number which appears exactly once.
A chess knight can move as indicated in the chess diagram below:
This time, we place our chess knight on any numbered key of a phone pad (indicated above), and the knight makes N-1 hops. Each hop must be from one key to another numbered key.
Each time it lands on a key (including the initial placement of the knight), it presses the number of that key, pressing N digits total.
How many distinct numbers can you dial in this manner?
Since the answer may be large, output the answer modulo 10^9 + 7.
Input: 1 Output: 10
Input: 2 Output: 20
Input: 3 Output: 46
- 1 <= N <= 5000
Credits To: leetcode.com
Leave me comments, if you have better ways to solve.
- Solution: XXX
Walk Through Testdata
// Blog link: https://code.dennyzhang.com/knight-dialer