Buggy python submission (verdict: Runtime Error):
import math
from functools import reduce
N = int(input())
A = input().split()
A = [int(a) for a in A]
B = []
for n in range(N):
  for i in range(1, (10^9)+1):
    A[n] = i
    b = reduce(math.gcd, A)
    B.append(b)
B_max = max(B)
print(B_max)

Fixed submission:
# PDF解説
N = int(input())
A = [int(a) for a in input().split()]

import fractions

L = []
# [gcd(0), gcd(0, A[0]), ... , gcd(0, A[0], A[1], ..., A[N-2])]
R = []
# [gcd(A[1], A[2], ... , A[N-1], 0), gcd(A[2], A[3], ... , A[N-1], 0), ... , gcd(0)]

L.append(0)
for i in range(0, N-1, 1):
  l = fractions.gcd(L[-1], A[i])
  L.append(l)

R.append(0)
for j in range(N-1, 0, -1):
  r = fractions.gcd(R[-1], A[j])
  R.append(r)
R.reverse()

ans = 0
for n in range(N):
  lr = fractions.gcd(L[n], R[n])
  ans = max(ans, lr)

print(ans)

Buggy python submission (verdict: Runtime Error):
import math
from functools import reduce
N = int(input())
A = input().split()
A = [int(a) for a in A]
B = []
for n in range(N):
  for i in range(1, (10^9)+1):
    A[n] = i
    b = reduce(math.gcd, A)
    B.append(b)
B_max = max(b)
print(B_max)

Fixed submission:
# PDF解説
N = int(input())
A = [int(a) for a in input().split()]

import fractions

L = []
# [gcd(0), gcd(0, A[0]), ... , gcd(0, A[0], A[1], ..., A[N-2])]
R = []
# [gcd(A[1], A[2], ... , A[N-1], 0), gcd(A[2], A[3], ... , A[N-1], 0), ... , gcd(0)]

L.append(0)
for i in range(0, N-1, 1):
  l = fractions.gcd(L[-1], A[i])
  L.append(l)

R.append(0)
for j in range(N-1, 0, -1):
  r = fractions.gcd(R[-1], A[j])
  R.append(r)
R.reverse()

ans = 0
for n in range(N):
  lr = fractions.gcd(L[n], R[n])
  ans = max(ans, lr)

print(ans)

Buggy python submission (verdict: Runtime Error):
import math
from functools import reduce
N = int(input())
A = input().split()
A = [int(a) for a in A]
B = []
for n in range(N):
  for i in range(1:(10^9)+1):
    A[n] = i
    b = reduce(math.gcd, A)
    B.append(b)
B_max = max(b)
print(B_max)

Fixed submission:
# PDF解説
N = int(input())
A = [int(a) for a in input().split()]

import fractions

L = []
# [gcd(0), gcd(0, A[0]), ... , gcd(0, A[0], A[1], ..., A[N-2])]
R = []
# [gcd(A[1], A[2], ... , A[N-1], 0), gcd(A[2], A[3], ... , A[N-1], 0), ... , gcd(0)]

L.append(0)
for i in range(0, N-1, 1):
  l = fractions.gcd(L[-1], A[i])
  L.append(l)

R.append(0)
for j in range(N-1, 0, -1):
  r = fractions.gcd(R[-1], A[j])
  R.append(r)
R.reverse()

ans = 0
for n in range(N):
  lr = fractions.gcd(L[n], R[n])
  ans = max(ans, lr)

print(ans)

Buggy python submission (verdict: Runtime Error):
import math
from functools import reduce
N = int(input())
A = input().split()
A = [int(a) for a in A]
B = []
for n in range(N):
  for i in range(1:(10^9)-1):
    A[n] = i
    b = reduce(math.gcd, A)
    B.append(b)
B_max = max(b)
print(B_max)

Fixed submission:
# PDF解説
N = int(input())
A = [int(a) for a in input().split()]

import fractions

L = []
# [gcd(0), gcd(0, A[0]), ... , gcd(0, A[0], A[1], ..., A[N-2])]
R = []
# [gcd(A[1], A[2], ... , A[N-1], 0), gcd(A[2], A[3], ... , A[N-1], 0), ... , gcd(0)]

L.append(0)
for i in range(0, N-1, 1):
  l = fractions.gcd(L[-1], A[i])
  L.append(l)

R.append(0)
for j in range(N-1, 0, -1):
  r = fractions.gcd(R[-1], A[j])
  R.append(r)
R.reverse()

ans = 0
for n in range(N):
  lr = fractions.gcd(L[n], R[n])
  ans = max(ans, lr)

print(ans)