Buggy python submission (verdict: Runtime Error):
# セグメント木。区間における要素の取得をO(logN)で行うことが可能である。
class SegTree():
    def __init__(self, lists, function, basement):
        self.n = len(lists)
        self.K = (self.n-1).bit_length()
        self.func = function
        self.basement = basement
        self.seg = [basement]*2**(self.K+1)

        for i in range(self.n):
            self.seg[i+2**self.K-1] = lists[i]

        for i in range(2**(self.K)-2, -1, -1):
            self.seg[i] = self.func(self.seg[2*i+1], self.seg[2*i+2])

    def update(self, k, value):
        # 0-indexでa[k]の値をvalueに変更
        k += 2**self.K-1
        self.seg[k] = value
        while k:
            k = (k-1)//2
            self.seg[k] = self.func(self.seg[k*2+1], self.seg[k*2+2])

    def query(self, p, q):
        # 0-indexで[p,q)の値を取得する
        if q <= p:
            return self.basement
        num = 2**self.K
        p += num-1
        q += num-2
        res = self.basement
        while q-p > 1:
            if p & 1 == 0:
                res = self.func(res, self.seg[p])
            if q & 1 == 1:
                res = self.func(res, self.seg[q])
                q -= 1
            p = p//2
            q = (q-1)//2
        if p == q:
            res = self.func(res, self.seg[p])
        else:
            res = self.func(self.func(res, self.seg[p]), self.seg[q])
        return res


#gcd on blackboard
#セグ木（区間gcd) verify
from math import gcd
N=int(input())
A=list(map(int,input().split()))
seg=SegTree(A,gcd,0)
ans=1
for i in range(-1,N):
    v=gcd(seg.query(0,i),seg.query(i+1,N))
    ans=max(v,ans)
print(ans)


Fixed submission:
#プログラムの例:
n=int(input())
listsT=list(map(int,input().split()))
from fractions import gcd
lists_left=[]
lists_right=[]
number1=0
number2=0
for i in range(n):
    if i==0:
        lists_left.append(0)
    if i==1:
        lists_left.append(listsT[0])
        number1=listsT[0]
    if i>=2:
        number1=gcd(number1,listsT[i-1])
        lists_left.append(number1)

number2=listsT[-1]
for j in range(n,0,-1):
    if j==n:
        lists_right.append(0)
    if j==n-1:
        lists_right.append(listsT[-1])
    if j<n-1:      
        number2=gcd(number2,listsT[j])  
        lists_right.append(number2)
ans=0
for x in range(n):
    if ans<= gcd(lists_right[x],lists_left[n-1-x]):
        ans=gcd(lists_right[x],lists_left[n-1-x])   
print(ans)

Buggy python submission (verdict: Runtime Error):
#プログラムの例:
n=int(input())
listsT=list(map(int,input().split()))
from math import gcd
lists_left=[]
lists_right=[]
number1=0
number2=0
for i in range(n):
    if i==0:
        lists_left.append(0)
    if i==1:
        lists_left.append(listsT[0])
        number1=listsT[0]
    if i>=2:
        number1=gcd(number1,listsT[i-1])
        lists_left.append(number1)

number2=listsT[-1]
for j in range(n,0,-1):
    if j==n:
        lists_right.append(0)
    if j==n-1:
        lists_right.append(listsT[-1])
    if j<n-1:      
        number2=gcd(number2,listsT[j])  
        lists_right.append(number2)
ans=0
for x in range(n):
    if ans<= gcd(lists_right[x],lists_left[n-1-x]):
        ans=gcd(lists_right[x],lists_left[n-1-x])   
print(ans)

Fixed submission:
#プログラムの例:
n=int(input())
listsT=list(map(int,input().split()))
from fractions import gcd
lists_left=[]
lists_right=[]
number1=0
number2=0
for i in range(n):
    if i==0:
        lists_left.append(0)
    if i==1:
        lists_left.append(listsT[0])
        number1=listsT[0]
    if i>=2:
        number1=gcd(number1,listsT[i-1])
        lists_left.append(number1)

number2=listsT[-1]
for j in range(n,0,-1):
    if j==n:
        lists_right.append(0)
    if j==n-1:
        lists_right.append(listsT[-1])
    if j<n-1:      
        number2=gcd(number2,listsT[j])  
        lists_right.append(number2)
ans=0
for x in range(n):
    if ans<= gcd(lists_right[x],lists_left[n-1-x]):
        ans=gcd(lists_right[x],lists_left[n-1-x])   
print(ans)