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: Wrong Answer)

import sys
sys.setrecursionlimit(2147483647)
input=sys.stdin.readline

def fact(arr):
  ans = 1
  for s in arr:
    ans *= s
    ans = ans % (int(10**9+7))
  return ans

def main():
  N, K = map(int, input().split(' '))
  A = list(map(int, input().split(' ')))
  Aplus = []
  Aminus = []
  for a in A:
    if(a >= 0):
      Aplus.append(a)
    else:
      Aminus.append(a)
  Aplus= sorted(Aplus, reverse=True)
  Aminus= sorted(Aminus)
  Aabs = sorted(A, key=lambda x:abs(x), reverse=True)
  plusnum=0
  minusnum=0
  for i in range(K):
    if(Aabs[i] >= 0):
      plusnum+=1
    else:
      minusnum += 1
  if(minusnum % 2 == 1):
    if(minusnum > 0 and plusnum > 0):
      if minusnum < len(Aminus):
        if (plusnum < len(Aplus)):
          if(abs(Aplus[plusnum] * Aminus[minusnum - 2]) > abs(Aplus[plusnum - 2] * Aminus[minusnum])):
            plusnum+=1
            minusnum-=1
          else:
            plusnum-=1
            minusnum+=1
        else:
          plusnum-=1
          minusnum+=1
      else:
        plusnum+=1
        minusnum-=1
  if(plusnum == 0):
    print(int(fact(Aminus[::-1][:minusnum])))
  else:    
    print(int(fact(Aplus[:plusnum]+Aminus[:minusnum])))

if __name__=='__main__':
  main()