Buggy python submission (verdict: Runtime Error):
import fractions
from functools import reduce
import copy

def gcd_list(numbers):
    return reduce(fractions.gcd, numbers)
  
n = int(input())
A = list(int(i) for i in (input().split()))

red_list = list(set(A))

ans = 0
tmp = 0
reduce_num = 0
for i in range(len(red_list)):
  if( i != 0): red_list.append(reduce_num)
  reduce_num = red_list.pop(0)
  tmp = gcd_list(red_list)
  if(ans < tmp):
    ans = tmp

print(ans)

Fixed submission:
import fractions
from functools import reduce

def gcd(*numbers):
    return reduce(fractions.gcd, numbers)
  
n = int(input())
A = list(int(i) for i in (input().split()))

front = []
end = []
for i in range(n):
  if(i == 0):
    front.append(gcd(*[A[0]]))
    end.append(gcd(*[A[n-1]]))
  else:
    front.append(gcd(*[front[i - 1],A[i]]))
    end.append(gcd(*[end[i - 1],A[n-1-i]]))

ans = 0
for i in range(n):
  if(i == 0):
    tmp = end[n-2]
  elif(i == n-1):
    tmp = front[n-2]
  else:
    tmp = gcd(*[front[i-1],end[n-2-i]])
  if(ans < tmp):
    ans = tmp
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import fractions
from functools import reduce
import copy

def gcd_list(numbers):
    return reduce(fractions.gcd, numbers)
  
n = int(input())
A = list(int(i) for i in (input().split()))

ans = 0
tmp = 0
reduce_num = 0
for i in range(n):
  if( i != 0): A.append(reduce_num)
  reduce_num = A.pop(0)
  tmp = gcd_list(A)
  if(ans < tmp):
    ans = tmp

print(ans)

Fixed submission:
import fractions
from functools import reduce

def gcd(*numbers):
    return reduce(fractions.gcd, numbers)
  
n = int(input())
A = list(int(i) for i in (input().split()))

front = []
end = []
for i in range(n):
  if(i == 0):
    front.append(gcd(*[A[0]]))
    end.append(gcd(*[A[n-1]]))
  else:
    front.append(gcd(*[front[i - 1],A[i]]))
    end.append(gcd(*[end[i - 1],A[n-1-i]]))

ans = 0
for i in range(n):
  if(i == 0):
    tmp = end[n-2]
  elif(i == n-1):
    tmp = front[n-2]
  else:
    tmp = gcd(*[front[i-1],end[n-2-i]])
  if(ans < tmp):
    ans = tmp
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import fractions
from functools import reduce
import copy

def gcd(*numbers):
    return reduce(fractions.gcd, numbers)

def gcd_list(numbers):
    return reduce(fractions.gcd, numbers)
  
n = int(input())
A = list(int(i) for i in (input().split()))

ans = 0
tmp = 0
for i in range(n):
  list = copy.copy(A)
  list.remove(A[i])
  tmp = gcd_list(list)
  if(ans < tmp):
    ans = tmp

print(ans)

Fixed submission:
import fractions
from functools import reduce

def gcd(*numbers):
    return reduce(fractions.gcd, numbers)
  
n = int(input())
A = list(int(i) for i in (input().split()))

front = []
end = []
for i in range(n):
  if(i == 0):
    front.append(gcd(*[A[0]]))
    end.append(gcd(*[A[n-1]]))
  else:
    front.append(gcd(*[front[i - 1],A[i]]))
    end.append(gcd(*[end[i - 1],A[n-1-i]]))

ans = 0
for i in range(n):
  if(i == 0):
    tmp = end[n-2]
  elif(i == n-1):
    tmp = front[n-2]
  else:
    tmp = gcd(*[front[i-1],end[n-2-i]])
  if(ans < tmp):
    ans = tmp
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import fractions
from functools import reduce
import copy

def gcd(*numbers):
    return reduce(fractions.gcd, numbers)

def gcd_list(numbers):
    return reduce(fractions.gcd, numbers)
  
n = int(input())
A = list(int(i) for i in (input().split()))

ans = 0
tmp = 0
for i in range(n):
  list = copy.copy(A)
  list.remove(A[i])
  tmp = gcd_list(list)
  if(ans < tmp):
    ans = tmp

print(ans)

Fixed submission:
import fractions
from functools import reduce

def gcd(*numbers):
    return reduce(fractions.gcd, numbers)
  
n = int(input())
A = list(int(i) for i in (input().split()))

front = []
end = []
for i in range(n):
  if(i == 0):
    front.append(gcd(*[A[0]]))
    end.append(gcd(*[A[n-1]]))
  else:
    front.append(gcd(*[front[i - 1],A[i]]))
    end.append(gcd(*[end[i - 1],A[n-1-i]]))

ans = 0
for i in range(n):
  if(i == 0):
    tmp = end[n-2]
  elif(i == n-1):
    tmp = front[n-2]
  else:
    tmp = gcd(*[front[i-1],end[n-2-i]])
  if(ans < tmp):
    ans = tmp
print(ans)