Buggy python submission (verdict: Runtime Error):
import copy
N, K=map(int,input().split())
A=list(map(int,input().split()))
B=sorted([(a,abs(a)) for a in A],key=lambda x:x[1],reverse=True)
R=10**9+7
P=1
minus=0
last_neg=-1
last_pos=-1
for i in range(K):
    if B[i][0]>0:
        if last_pos != -1:
            P = (P * B[last_pos][1]) % R
        last_pos=i
    else:
        if last_neg != -1:
            P = (P * B[last_neg][1]) % R
        minus+=1
        last_neg=i
F=copy.copy(P)
if last_pos!=-1:
    F=(F*B[last_pos][1]) % R
if last_neg!=-1:
    F=(F*B[last_neg][1]) % R
if minus%2==1:
    if K == N:
        print(-F)
        exit()
    first_neg=-1
    first_pos=-1
    count=[0,0]
    for i in range(K,N):
        if count[0]==0 and B[i][0]>0:
            first_pos=i
            count[0]=1
        elif count[1]==0 and B[i][0]<0:
            first_neg=i
            count[1]=1
        elif count==[1,1]:
            break
    if first_pos==-1 and last_pos==-1:
        P = 1
        for i in range(K):
           P = (P * B[N - i - 1][0]) % R
        print(P)
        exit()
    list_product=[]
    if first_neg!=-1:
        list_product.append((P*B[last_neg][1]*B[first_neg][1]) %R)
    if first_pos!=-1:
        P1=(P*B[first_pos][1]) %R
        if last_pos!=-1:
            P1=(P1*B[last_pos][1]) %R
        list_product.append(P1)
    print(max(list_product))
else:
    print(F)


Fixed submission:
import copy
N, K=map(int,input().split())
A=list(map(int,input().split()))
B=sorted([(a,abs(a)) for a in A],key=lambda x:x[1],reverse=True)
R=10**9+7
P=1
minus=0
last_neg=-1
last_pos=-1
for i in range(K):
    if B[i][0]>0:
        if last_pos != -1:
            P = (P * B[last_pos][1]) % R
        last_pos=i
    elif B[i][0]<0:
        if last_neg != -1:
            P = (P * B[last_neg][1]) % R
        minus+=1
        last_neg=i
    else:
        print(0)
        exit()
F=copy.copy(P)
if last_pos!=-1:
    F=(F*B[last_pos][1]) % R
if last_neg!=-1:
    F=(F*B[last_neg][1]) % R
if minus%2==1:
    if K == N:
        print(-F %R)
        exit()
    first_neg=-1
    first_pos=-1
    count=[0,0]
    for i in range(K,N):
        if count[0]==0 and B[i][0]>0:
            first_pos=i
            count[0]=1
        elif count[1]==0 and B[i][0]<0:
            first_neg=i
            count[1]=1
        elif count==[1,1]:
            break
    if first_pos==-1 and last_pos==-1:
        P = 1
        for i in range(K):
           P = (P * B[N - i - 1][0]) % R
        print(P)
        exit()
    if first_pos==-1 and first_neg==-1:
        print(0)
        exit()
    list_product=[]
    if first_neg!=-1 and last_pos!=-1:
        list_product.append(B[last_neg][1]*B[first_neg][1])
    if first_pos!=-1:
        P1=B[first_pos][1]
        if last_pos!=-1:
            P1=P1*B[last_pos][1]
        list_product.append(P1)
    print(max(list_product)*P %R)
else:
    print(F)

Buggy python submission (verdict: Runtime Error):
N, K=map(int,input().split())
A=list(map(int,input().split()))
B=sorted([(a,abs(a)) for a in A],key=lambda x:x[1],reverse=True)
R=10**9+7
P=1
minus=0
last_neg=-1
last_pos=-1
for i in range(K):
    if B[i][0]>0:
        if last_pos != -1:
            P = (P * B[last_pos][1]) % R
        last_pos=i
    else:
        if last_neg != -1:
            P = (P * B[last_neg][1]) % R
        minus+=1
        last_neg=i
if minus%2==1:
    first_neg=-1
    first_pos=-1
    count=[0,0]
    for i in range(K,N):
        if count[0]==0 and B[i][0]>0:
            first_pos=i
            count[0]=1
            if last_neg<last_pos:
                count[1]=1
                break
        elif count[1]==0 and B[i][0]<0:
            first_neg=i
            count[1]=1
            if last_pos<last_neg:
                count[0]=1
                break
        elif count==[1,1]:
            break
    if first_pos==-1 and last_pos==-1:
        P = 1
        for i in range(K):
           P = (P * B[N - i - 1][0]) % R
        print(P)
        exit()
    list_product=[]
    if first_neg!=-1:
        list_product.append((P*B[last_neg][1]*B[first_neg][1]) %R)
    if first_pos!=-1 and last_pos!=-1:
        list_product.append((P*B[last_pos][1]*B[first_pos][1]) %R)
    print(max(list_product))
else:
    if last_pos!=-1:
        print((P*B[last_pos][1]*B[last_neg][1]) %R)
    else:
        print((P*B[last_neg][1]) % R)

Fixed submission:
import copy
N, K=map(int,input().split())
A=list(map(int,input().split()))
B=sorted([(a,abs(a)) for a in A],key=lambda x:x[1],reverse=True)
R=10**9+7
P=1
minus=0
last_neg=-1
last_pos=-1
for i in range(K):
    if B[i][0]>0:
        if last_pos != -1:
            P = (P * B[last_pos][1]) % R
        last_pos=i
    elif B[i][0]<0:
        if last_neg != -1:
            P = (P * B[last_neg][1]) % R
        minus+=1
        last_neg=i
    else:
        print(0)
        exit()
F=copy.copy(P)
if last_pos!=-1:
    F=(F*B[last_pos][1]) % R
if last_neg!=-1:
    F=(F*B[last_neg][1]) % R
if minus%2==1:
    if K == N:
        print(-F %R)
        exit()
    first_neg=-1
    first_pos=-1
    count=[0,0]
    for i in range(K,N):
        if count[0]==0 and B[i][0]>0:
            first_pos=i
            count[0]=1
        elif count[1]==0 and B[i][0]<0:
            first_neg=i
            count[1]=1
        elif count==[1,1]:
            break
    if first_pos==-1 and last_pos==-1:
        P = 1
        for i in range(K):
           P = (P * B[N - i - 1][0]) % R
        print(P)
        exit()
    if first_pos==-1 and first_neg==-1:
        print(0)
        exit()
    list_product=[]
    if first_neg!=-1 and last_pos!=-1:
        list_product.append(B[last_neg][1]*B[first_neg][1])
    if first_pos!=-1:
        P1=B[first_pos][1]
        if last_pos!=-1:
            P1=P1*B[last_pos][1]
        list_product.append(P1)
    print(max(list_product)*P %R)
else:
    print(F)

Buggy python submission (verdict: Runtime Error):
N, K=map(int,input().split())
A=list(map(int,input().split()))
B=sorted([(a,abs(a)) for a in A],key=lambda x:x[1],reverse=True)
R=10**9+7
P=1
minus=0
last_neg=-1
last_pos=-1
for i in range(K):
    if i!=0:
        P=(P*B[i-1][1]) %R
    if B[i][0]>0:
        last_pos=i
    else:
        minus+=1
        last_neg=i
if minus%2==1:
    first_neg=-1
    first_pos=-1
    count=[0,0]
    for i in range(K,N):
        if count[0]==0 and B[i][0]>0:
            first_pos=i
            count[0]=1
            if last_neg<last_pos:
                count[1]=1
                break
        elif count[1]==0 and B[i][0]<0:
            first_neg=i
            count[1]=1
            if last_pos<last_neg:
                count[0]=1
                break
        elif count==[1,1]:
            break
    if last_pos==-1 and first_pos==-1:
        P=1
        for i in range(K):
            P=(P*B[N-i-1][0]) %R
        print(P)
        exit()
    list_product=[]
    if first_neg!=-1:
        list_product.append((P*B[first_neg][1]) %R)
    if first_pos!=-1:
        list_product.append((P*B[first_pos][1]) %R)
    print(max(list_product))
else:
    print(P*B[K-1][1] %R)


Fixed submission:
import copy
N, K=map(int,input().split())
A=list(map(int,input().split()))
B=sorted([(a,abs(a)) for a in A],key=lambda x:x[1],reverse=True)
R=10**9+7
P=1
minus=0
last_neg=-1
last_pos=-1
for i in range(K):
    if B[i][0]>0:
        if last_pos != -1:
            P = (P * B[last_pos][1]) % R
        last_pos=i
    elif B[i][0]<0:
        if last_neg != -1:
            P = (P * B[last_neg][1]) % R
        minus+=1
        last_neg=i
    else:
        print(0)
        exit()
F=copy.copy(P)
if last_pos!=-1:
    F=(F*B[last_pos][1]) % R
if last_neg!=-1:
    F=(F*B[last_neg][1]) % R
if minus%2==1:
    if K == N:
        print(-F %R)
        exit()
    first_neg=-1
    first_pos=-1
    count=[0,0]
    for i in range(K,N):
        if count[0]==0 and B[i][0]>0:
            first_pos=i
            count[0]=1
        elif count[1]==0 and B[i][0]<0:
            first_neg=i
            count[1]=1
        elif count==[1,1]:
            break
    if first_pos==-1 and last_pos==-1:
        P = 1
        for i in range(K):
           P = (P * B[N - i - 1][0]) % R
        print(P)
        exit()
    if first_pos==-1 and first_neg==-1:
        print(0)
        exit()
    list_product=[]
    if first_neg!=-1 and last_pos!=-1:
        list_product.append(B[last_neg][1]*B[first_neg][1])
    if first_pos!=-1:
        P1=B[first_pos][1]
        if last_pos!=-1:
            P1=P1*B[last_pos][1]
        list_product.append(P1)
    print(max(list_product)*P %R)
else:
    print(F)

Buggy python submission (verdict: Runtime Error):
N, K=map(int,input().split())
A=list(map(int,input().split()))
B=sorted([(a,abs(a)) for a in A],key=lambda x:x[1],reverse=True)
R=10**9+7
P=1
minus=0
last_neg=-1
last_pos=-1
for i in range(K):
    if i!=0:
        P=P*B[i-1][1]
    if B[i][0]>0:
        last_pos=i
    else:
        minus+=1
        last_neg=i
if minus%2==1:
    first_neg=-1
    first_pos=-1
    count=[0,0]
    for i in range(K,N):
        if count[0]==0 and B[i][0]>0:
            first_pos=i
            count[0]=1
            if last_neg<last_pos:
                count[1]=1
                break
        elif count[1]==0 and B[i][0]<0:
            first_neg=i
            count[1]=1
            if last_pos<last_neg:
                count[0]=1
                break
        elif count==[1,1]:
            break
    if last_pos==-1 and first_pos==-1:
        P=1
        for i in range(K):
            P=(P*B[N-i-1][0]) %R
        print(P)
        exit()
    list_product=[]
    if first_neg!=-1:
        list_product.append((P*B[first_neg][1]) %R)
    if first_pos!=-1:
        list_product.append((P*B[first_pos][1]) %R)
    print(max(list_product))
else:
    print(P*B[K-1][1] %R)

Fixed submission:
import copy
N, K=map(int,input().split())
A=list(map(int,input().split()))
B=sorted([(a,abs(a)) for a in A],key=lambda x:x[1],reverse=True)
R=10**9+7
P=1
minus=0
last_neg=-1
last_pos=-1
for i in range(K):
    if B[i][0]>0:
        if last_pos != -1:
            P = (P * B[last_pos][1]) % R
        last_pos=i
    elif B[i][0]<0:
        if last_neg != -1:
            P = (P * B[last_neg][1]) % R
        minus+=1
        last_neg=i
    else:
        print(0)
        exit()
F=copy.copy(P)
if last_pos!=-1:
    F=(F*B[last_pos][1]) % R
if last_neg!=-1:
    F=(F*B[last_neg][1]) % R
if minus%2==1:
    if K == N:
        print(-F %R)
        exit()
    first_neg=-1
    first_pos=-1
    count=[0,0]
    for i in range(K,N):
        if count[0]==0 and B[i][0]>0:
            first_pos=i
            count[0]=1
        elif count[1]==0 and B[i][0]<0:
            first_neg=i
            count[1]=1
        elif count==[1,1]:
            break
    if first_pos==-1 and last_pos==-1:
        P = 1
        for i in range(K):
           P = (P * B[N - i - 1][0]) % R
        print(P)
        exit()
    if first_pos==-1 and first_neg==-1:
        print(0)
        exit()
    list_product=[]
    if first_neg!=-1 and last_pos!=-1:
        list_product.append(B[last_neg][1]*B[first_neg][1])
    if first_pos!=-1:
        P1=B[first_pos][1]
        if last_pos!=-1:
            P1=P1*B[last_pos][1]
        list_product.append(P1)
    print(max(list_product)*P %R)
else:
    print(F)