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
.
Example 1:
Input: 1 Output: 10
Example 2:
Input: 2 Output: 20
Example 3:
Input: 3 Output: 46
Note:
1 <= N <= 5000