Score : $300$ points
There is a box containing $N$ balls. The $i$-th ball has the integer $A_i$ written on it. Snuke can perform the following operation any number of times:
Determine whether it is possible for Snuke to reach the state where the box contains a ball on which the integer $K$ is written.
Input is given from Standard Input in the following format:
$N$ $K$ $A_1$ $A_2$ $...$ $A_N$
If it is possible for Snuke to reach the state where the box contains a ball on which the integer $K$ is written, print POSSIBLE
; if it is not possible, print IMPOSSIBLE
.
3 7 9 3 4
POSSIBLE
First, take out the two balls $9$ and $4$, and return them back along with a new ball, $abs(9-4)=5$.
Next, take out $3$ and $5$, and return them back along with $abs(3-5)=2$.
Finally, take out $9$ and $2$, and return them back along with $abs(9-2)=7$.
Now we have $7$ in the box, and the answer is therefore POSSIBLE
.
3 5 6 9 3
IMPOSSIBLE
No matter what we do, it is not possible to have $5$ in the box. The answer is therefore IMPOSSIBLE
.
4 11 11 3 7 15
POSSIBLE
The box already contains $11$ before we do anything. The answer is therefore POSSIBLE
.
5 12 10 2 8 6 4
IMPOSSIBLE