Buggy python submission (verdict: Runtime Error):
import numpy as np

x, y, z, k = list(map(int, input().split()))
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))

AA, BB = np.meshgrid(A,B)
AB = AA+BB
AB = np.sort(AB.flatten())[::-1]

ABAB, CC = np.meshgrid(AB,C)
ABC = ABAB+CC
ABC = np.sort(ABC.flatten())[::-1]

for abc in ABC:
    print(abc)

Fixed submission:
x, y, z, k = list(map(int, input().split()))
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))

A.sort(reverse=True)
B.sort(reverse=True)
C.sort(reverse=True)

ABC = []
for x, a in enumerate(A):
    if x+1 > 3000:
        break
        
    for y, b in enumerate(B):
        if (x+1)*(y+1) > 3000:
            break
    
        for z, c in enumerate(C):
            if (x+1)*(y+1)*(z+1) > 3000:
                break
            
            ABC.append(a+b+c)
            
ABC.sort(reverse=True)
ABC = ABC[:k]

for abc in ABC:
    print(abc)

Buggy python submission (verdict: Time Limit Exceeded):
x, y, z, k = list(map(int, input().split()))
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))

AB = []
for a in A:
    for b in B:
        AB.append(a+b)
        
AB.sort(reverse=True)
AB = AB[:k]

ABC = []
for ab in AB:
    for c in C:
        ABC.append(ab+c)

ABC.sort(reverse=True)
ABC = ABC[:k]

for abc in ABC:
    print(abc)

Fixed submission:
x, y, z, k = list(map(int, input().split()))
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))

A.sort(reverse=True)
B.sort(reverse=True)
C.sort(reverse=True)

ABC = []
for x, a in enumerate(A):
    if x+1 > 3000:
        break
        
    for y, b in enumerate(B):
        if (x+1)*(y+1) > 3000:
            break
    
        for z, c in enumerate(C):
            if (x+1)*(y+1)*(z+1) > 3000:
                break
            
            ABC.append(a+b+c)
            
ABC.sort(reverse=True)
ABC = ABC[:k]

for abc in ABC:
    print(abc)

Buggy python submission (verdict: Runtime Error):
import operator

di = {}

for i, (a, b, c) in enumerate(zip(a_, b_, c_)):
    di['a{}'.format(i)] = a
    di['b{}'.format(i)] = b
    di['c{}'.format(i)] = c

if len(di) > 3000:
    di = sorted(di.items(), reverse=True, key=operator.itemgetter(1))
    di = di[:3000]


a_li = []
b_li = []
c_li = []

for key, value in di.items():
    if 'a' in key:
        a_li.append(value)
    elif 'b' in key:
        b_li.append(value)
    elif 'c' in key:
        c_li.append(value)

ans = []
for a in a_li:
    for b in b_li:
        for c in c_li:
            ans.append(a+b+c)

ans.sort(reverse=True)

if len(ans) > 3000:
    for count, i in enumerate(ans):
        print(i)
        if count==2999:
            break
else:
    for count, i in enumerate(ans):
        print(i)

Fixed submission:
x, y, z, k = list(map(int, input().split()))
A = list(map(int, input().split()))
B = list(map(int, input().split()))
C = list(map(int, input().split()))

A.sort(reverse=True)
B.sort(reverse=True)
C.sort(reverse=True)

ABC = []
for x, a in enumerate(A):
    if x+1 > 3000:
        break
        
    for y, b in enumerate(B):
        if (x+1)*(y+1) > 3000:
            break
    
        for z, c in enumerate(C):
            if (x+1)*(y+1)*(z+1) > 3000:
                break
            
            ABC.append(a+b+c)
            
ABC.sort(reverse=True)
ABC = ABC[:k]

for abc in ABC:
    print(abc)