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()))

list.sort(a, reverse=True)
total = 1
count_a = 0
count_b = N-1


if a[0]<0 and K%2 != 0:
	for i in range(N):
		a[i] = abs(a[i])
	list.sort(a, reverse=False)
	for i in range(K):
		total *= a[i]
		total  =total%(10**9 +7)
	total *= -1
	total  =total%(10**9 +7)
else:
	while K>0:

		if K %2 == 1:
			total += max( a[count_a], a[count_b])
			K -= 1
		if K> 1:
			if a[count_a]*a[count_a+1] >a[count_b]*a[count_b-1]:
				total *= a[count_a] * a[count_a+1]
				total  =total%(10**9 +7)
				count_a += 2
			else:
				total *= a[count_b]*a[count_b-1]
				count_b -= 2
				total  =total%(10**9 +7)
			K-=2
		else:
			total *= max( a[count_a], a[count_b])
			total  =total%(10**9 +7)
		K -= 1
print(total)