Here are some interesting problems you can try to solve it. Note: They are not actually hard.
You are given a number with $N$ digits. Now, I ask you to divide the number into $K$ numbers such that the product of these numbers is maximized.
Input:
4 2
1231
Output:
62
There are $N$ command cards. A number $k$ on a card satisfies that $1 \leq k \leq 4$. You can use these command cards to send command to a bot on a track and let the bot step $k$ steps foward, and you can use these cards in any order you want to. The track is divided into $M$ grids, by stopping at a grid at $i^{th}$ position, you will get $a_i$ points. Find the maximum point you can get.
Note: the number along the way bot passes does not count to the total sum. Only the numbers at where exactly it stops at count
Input
9 5
6 10 14 2 8 8 18 5 17
1 3 1 2 1
Output
73