Problem p03061 (python)

Fixed submission:
# -*- coding: utf-8 -*-

import sys
if sys.version_info.minor >= 5: from math import gcd
else: from fractions import gcd
from functools import reduce

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def gcd_list(nums): return reduce(gcd, nums, nums[0])
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

N=INT()
A=LIST()

L=[0]*N
L[0]=A[0]
for i in range(1, N):
    L[i]=gcd(L[i-1], A[i])
R=[0]*N
R[-1]=A[-1]
for i in range(N-2, -1, -1):
    R[i]=gcd(R[i+1], A[i])

ans=0
for i in range(N):
    if i==0:
        ans=max(ans, R[1])
    elif i==N-1:
        ans=max(ans, L[-2])
    else:
        ans=max(ans, gcd(L[i-1], R[i+1]))
print(ans)

Buggy submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-

import sys
if sys.version_info.minor >= 5: from math import gcd
else: from fractions import gcd

def input(): return sys.stdin.readline().strip()
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(): return list(map(int, input().split()))
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = float('inf')
MOD = 10 ** 9 + 7

class SegTree:
    """
    以下のクエリを処理する
    1.update:  i番目の値をxに更新する
    2.get_val: 区間[l, r)の値を得る
    """
 
    def __init__(self, n, func, init):
        """
        :param n: 要素数
        :param func: 値の操作に使う関数(min, max, addなど)
        :param init: 要素の初期値
        """
        n += 1
        self.n = n
        self.func = func
        self.init = init
        # nより大きい2の冪数
        n2 = 1
        while n2 < n:
            n2 <<= 1
        self.n2 = n2
        self.tree = [self.init] * (n2 << 1)
 
    def update(self, i, x):
        """
        i番目の値をxに更新
        :param i: index(0-indexed)
        :param x: update value
        """
        i += self.n2
        self.tree[i] = x
        while i > 1:
            self.tree[i >> 1] = x = self.func(x, self.tree[i ^ 1])
            i >>= 1
 
    def get_val(self, a, b):
        """
        [a, b)の値を得る
        :param a: index(0-indexed)
        :param b: index(0-indexed)
        """
        return self._get_val(a, b, 1, 0, self.n2)
 
    def _get_val(self, a, b, k, l, r):
        """
        [a, b)の値を得る内部関数
        :param k: 現在調べている区間のtree内index
        :param l, r: kが表す区間の左右端index [l, r)
        :return: kが表す区間と[a, b)の共通区間内での最小値。共通区間を持たない場合は初期値
        """
        # 範囲外なら初期値
        if r <= a or b <= l:
            return self.init
        # [a,b)が完全に[l,r)を包含するならtree[k]の値を採用
        if a <= l and r <= b:
            return self.tree[k]
        # 一部だけ範囲内なら2つに分けて再帰的に調査
        m = (l + r) // 2
        return self.func(
            self._get_val(a, b, k << 1, l, m),
            self._get_val(a, b, (k << 1) + 1, m, r)
        )

N=INT()
A=LIST()

st=SegTree(N+2, gcd, 0)
for i in range(1, N+1):
    st.update(i, A[i])

ans=0
for i in range(1, N+1):
    ans=max(ans, gcd(st.get_val(0, i), st.get_val(i+1, N+2)))
print(ans)