Buggy python submission (verdict: Runtime Error):
def main():

    N, K = map(int, input().split())
    A = list(map(int, input().split()))

    mod = pow(10, 9) + 7

    pos = []
    neg = []
    zero = 0
    for v in A:
        if v > 0: pos.append(v)
        elif v < 0: neg.append(v)
        else: zero += 1

    # zero is needed
    if len(pos) + len(neg) < K:
        return 0

    pos.sort(reverse = True)
    neg.sort()

    cnt_p, cnt_n = 0, 0
    h = []
    for v in pos:
        h.append([v, 1])
    for v in neg:
        h.append([-v, -1])

    h.sort(reverse = True)
    v = 1
    for k in range(K):
        if h[k][1] > 0:
            cnt_p += 1
        else:
            cnt_n += 1

    if cnt_n % 2 == 0: # when positive
        v = 1
        for i in range(cnt_p):
            v *= pos[i]
            v %= mod
        for j in range(cnt_n):
            v *= abs(neg[j])
            v %= mod
        return v % mod
    else: # when negative
        if cnt_p < len(pos) and cnt_n < len(neg) and cnt_p > 0 and cnt_n > 0: # both are not full
            if pos[cnt_p] * pos[cnt_p-1] > abs(neg[cnt_n]) * abs(neg[cnt_n-1]):
                cnt_p += 1
                cnt_n -= 1
            else:
                cnt_p -= 1
                cnt_n += 1
            v = 1
            for i in range(cnt_p):
                v *= pos[i]
                v %= mod
            for j in range(cnt_n):
                v *= abs(neg[j])
                v %= mod
            return v
        elif cnt_p < len(pos) and cnt_n > 0:
            cnt_p += 1
            cnt_n -= 1
            v = 1
            for i in range(cnt_p):
                v *= pos[i]
                v %= mod
            for j in range(cnt_n):
                v *= abs(neg[j])
                v %= mod
            return v % mod
        elif cnt_n < len(neg) and cnt_p > 0:
            cnt_p -= 1
            cnt_n += 1
            for i in range(cnt_p):
                v *= pos[i]
                v %= mod
            for j in range(cnt_n):
                v *= abs(neg[j])
                v %= mod
            return v % mnod
        else:
            if zero > 0:
                return 0
            else:
                pos.sort()
                neg.sort(reverse = True)
                h = []
                for v in pos:
                    h.append([v, 1])
                for v in neg:
                    h.append([-v, -1])
                v = 1
                for i in range(K):
                    v *= h[i][0] * h[i][1]
                    v %= mod
                return v % mod



if __name__ == '__main__':
    print(main())

Fixed submission:
def main():

    N, K = map(int, input().split())
    A = list(map(int, input().split()))

    mod = pow(10, 9) + 7

    pos = []
    neg = []
    zero = 0
    for v in A:
        if v > 0: pos.append(v)
        elif v < 0: neg.append(v)
        else: zero += 1

    # zero is needed
    if len(pos) + len(neg) < K:
        return 0

    pos.sort(reverse = True)
    neg.sort()

    cnt_p, cnt_n = 0, 0
    h = []
    for v in pos:
        h.append([v, 1])
    for v in neg:
        h.append([-v, -1])

    h.sort(reverse = True)
    v = 1
    for k in range(K):
        if h[k][1] > 0:
            cnt_p += 1
        else:
            cnt_n += 1

    if cnt_n % 2 == 0: # when positive
        v = 1
        for i in range(cnt_p):
            v *= pos[i]
            v %= mod
        for j in range(cnt_n):
            v *= neg[j]
            v %= mod
        return v
    else: # when negative
        if cnt_p < len(pos) and cnt_n < len(neg) and cnt_p > 0: # both are not full
            # if abs(neg[cnt_n]) / pos[cnt_p-1] < pos[cnt_p] / abs(neg[cnt_n-1]):
            if pos[cnt_p] * pos[cnt_p-1] > abs(neg[cnt_n]) * abs(neg[cnt_n-1]):
                cnt_p += 1
                cnt_n -= 1
            else:
                cnt_p -= 1
                cnt_n += 1
            v = 1
            for i in range(cnt_p):
                v *= pos[i]
                v %= mod
            for j in range(cnt_n):
                v *= neg[j]
                v %= mod
            return v
        elif cnt_p < len(pos) and cnt_n > 0:
            cnt_p += 1
            cnt_n -= 1
            v = 1
            for i in range(cnt_p):
                v *= pos[i]
                v %= mod
            for j in range(cnt_n):
                v *= neg[j]
                v %= mod
            return v
        elif cnt_n < len(neg) and cnt_p > 0:
            cnt_p -= 1
            cnt_n += 1
            for i in range(cnt_p):
                v *= pos[i]
                v %= mod
            for j in range(cnt_n):
                v *= neg[j]
                v %= mod
            return v
        else:
            if zero > 0:
                return 0
            else:
                h.sort()
                v = 1
                for i in range(K):
                    v *= h[i][0] * h[i][1]
                    v %= mod
                return v



if __name__ == '__main__':
    print(main())