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 numpy as np
N,K=map(int, input().split())
A =list(map(int,input().split()))
MOD = 10 ** 9 + 7
if N==K:
  ans0 = 1
  for a in A[0:N]:
    ans0 *= a
    ans0 %= MOD
  print(ans0)
  exit()
A=sorted(A)  
if (K%2==1 and A[-1]<0):
  ans1 = 1
  for a in A[N-K:N]:
    ans1 *= a
    ans1 %= MOD
  print(ans1)
  exit()

A=sorted(A, key=lambda x:abs(x), reverse=True)
AA=[np.sign(i) for i in A]

ansA = 1
for a in A[0:K]:
  ansA *= a
  ansA %= MOD
ansAA = AA[0:K].count(-1)%2
if ansA==0 or ansAA==0:
  print(ansA)
  exit()

while ansA>0:
  ansA-=MOD

B1=A[0:K]
B2=sorted(A[K:N])
Bp=[i for i in A[0:K] if i>0]
Bm=[i for i in A[0:K] if i<0]

if B2[0]>0:B2.insert(0,0)
if B2[-1]<0:B2.insert(-1,0)
if not Bp:Bp.insert(0,B1[-1])
if not Bm:Bm.insert(0,B1[0])
  
#print(Bp,Bm,B2)

B1.remove(Bp[-1])
B1.append(min(B2[0],0))
#print(B1)
ansB = 1
for a in B1[0:K]:
  ansB *= a
  ansB %= MOD

C1=A[0:K]
C1.remove(Bm[-1])
C1.append(max(B2[-1],0))

ansC = 1
for a in C1[0:K]:
  ansC *= a
  ansC %= MOD

if abs(Bp[-1]*B2[-1])-abs(Bm[0]*B2[0])>=0:
  print(ansC)
#elif abs(Bp[-1]*B2[-1])-abs(Bm[0]*B2[0])>0:
#  print(ansC)
else: print(ansB)

#print(max(ansB,ansC))