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)

import numpy as np
n,k=map(int,input().split())
a=list(map(int,input().split()))
a.sort()
s=1
c=0
l=0
r=-1
while True:
    if k-c>=2:
        if a[r]*a[r-1]>=a[l]*a[l+1]:
            s*=a[r]*a[r-1]
            r-=2
            c+=2
        else:
            s*=a[l]*a[l+1]
            l+=2
            c+=2
    else:
        if a[r]<0:
            s=1
            a=np.abs(a)
            a=list(a)
            a.sort()
            while True:
                s*=a[c1]
                c1+=1
                s%=10**9+7
                if c1==k:
                    s=-s
                    print(s%10**9+7)
                    exit()
        else:s*=a[r]
        c+=1
    s%=10**9+7
    if k==c:break
print(s)