Problem:
Score : 500 points

Problem Statement

Given are N integers A_1,\ldots,A_N.

We will choose exactly K of these elements. Find the maximum possible product of the chosen elements.

Then, print the maximum product modulo (10^9+7), using an integer between 0 and 10^9+6 (inclusive).

Constraints

1 \leq K \leq N \leq 2\times 10^5

|A_i| \leq 10^9

Input

Input is given from Standard Input in the following format:

N K
A_1 \ldots A_N

Output

Print the maximum product modulo (10^9+7), using an integer between 0 and 10^9+6 (inclusive).

Sample Input 1

4 2
1 2 -3 -4

Sample Output 1

12

The possible products of the two chosen elements are 2, -3, -4, -6, -8, and 12, so the maximum product is 12.

Sample Input 2

4 3
-1 -2 -3 -4

Sample Output 2

1000000001

The possible products of the three chosen elements are -24, -12, -8, and -6, so the maximum product is -6.

We print this value modulo (10^9+7), that is, 1000000001.

Sample Input 3

2 1
-1 1000000000

Sample Output 3

1000000000

The possible products of the one chosen element are -1 and 1000000000, so the maximum product is 1000000000.

Sample Input 4

10 10
1000000000 100000000 10000000 1000000 100000 10000 1000 100 10 1

Sample Output 4

999983200

Be sure to print the product modulo (10^9+7).

Solution in Python (3.8.2) (judge verdict: Runtime Error)

def mult(lis):
  ret=1
  for i in lis:
    ret*=i
    ret%=1000000007
  return ret
n,k=map(int,input().split())
a=list(map(int,input().split()))
minus=[]
plus=[]
ch=[]
for i in a:
  if i<0:
    minus.append(i)
  else:
    plus.append(i)
if len(plus)==0 and k%2:
  minus.sort(reverse=True)
  ch.extend(minus[:k])
else:
  pls=True
  a.sort(key=lambda x: abs(x), reverse=True)
  print(a)
  while k>0:
    inp=a.pop(0)
    if inp<0:
      if k==1 and pls:
        continue
      pls^=1
    ch.append(inp)
    k-=1
print(mult(ch))