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)

# coding: utf-8
N,K=map(int,input().split())
A=list(map(int,input().split()))
MOD=10**9+7

ans=1

if K==N:
    for i in range(N):
        ans*=A[i]
        if ans>0:
            ans=ans%MOD
elif max(A)<0 and K%2==1:
    A.sort(reverse=True)
    for i in range(K):
        ans*=A[i]
        if ans>0:
            ans=ans%MOD
else:
    Ap=[]
    Am=[]
    
    for i in range(N):
        if A[i]>0:
            Ap.append(A[i])
        else:
            Am.append(A[i])
        

    Ap.sort(reverse=True)
    Am.sort()
    
    if K%2==1 and Ap:
        ans*=Ap.pop(0)
    
    if len(Ap)%2==1:
        Ap.append(1)
    
    P=[]
    
    for i in range(len(Ap)//2):
        P.append(Ap[i*2]*Ap[i*2+1])
    
    for i in range(len(Am)//2):
        P.append(Am[i*2]*Am[i*2+1])
    
    P.sort(reverse=True)
    
    for i in range(K//2):
        ans*=P[i]
        ans=ans%MOD

print(ans%MOD)