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)

n,k = map(int,input().split())
a = list(map(int,input().split()))
mod = 10**9+7
a.sort()
mi = []
pl = []
zero = 0
for i in a:
    if i < 0:
        mi.append(i)
    elif i == 0:
        zero += 1
    else:
        pl.append(i)

if n-zero < k:
    print(0)
    exit()
if mi == []:
    ans = 1
    count = 0
    while count < k:
        ans *= a[-1-count]
        ans %= mod
        count += 1
    print(ans)
    
    exit()
if pl == []:
    if k%2:
        if zero:
            print(0)
        else:
            ans = 1
            count = 0
            while count < k:
                ans *= a[-1-count]
                ans %= mod
                count += 1
            print(ans)
            
    else:
        ans = 1
        count = 0
        while count < k:
            ans *= a[count]
            ans %= mod
            count += 1
        print(ans)
        
    exit()

ans = 0
sm = [mi[-1]]
for i in range(len(mi)-2,-1,-1):
    sm.append((sm[-1]*mi[i])%mod)
sp = [pl[-1]]
for i in range(len(pl)-2,-1,-1):
    sp.append((sp[-1]*pl[i])%mod)

for i in range(0,k+1,2):
    j = k-i
    
    if i > len(mi) or j > len(pl):
        continue
    x = 1
    if i > 0:
        x *= sm[i-1]
        x %= mod
    if j > 0:
        x *= sp[j-1]
        x %= mod
    
    ans = max(ans,x)
print(ans)