Score : 500 points
There are N boxes arranged in a circle. The i-th box contains A_i stones.
Determine whether it is possible to remove all the stones from the boxes by repeatedly performing the following operation:
Note that the operation cannot be performed if there is a box that does not contain enough number of stones to be removed.
The input is given from Standard Input in the following format:
N A_1 A_2 … A_N
If it is possible to remove all the stones from the boxes, print YES
. Otherwise, print NO
.
5 4 5 1 2 3
YES
All the stones can be removed in one operation by selecting the second box.
5 6 9 12 10 8
YES
4 1 2 3 1
NO