Language: C++

#include "bits/stdc++.h"
using namespace std;
#define pb          push_back
#define mp          make_pair
#define ll          long long
#define pii         pair<ll, ll>
#define vi          vector<ll>
#define vii         vector<pii>
#define mi          map<ll, ll>
#define mii         map<pii, ll>
#define all(a)      (a).begin(),(a).end()
#define x           first
#define y           second
#define sz(x)       (int)x.size()
#define endl        '\n'
#define hell        1000000007
#define debug(x) cout << '>' << #x << ':' << x << endl;
#define rep(i,a,b)  for(int i=a;i<b;i++)
#define rev(i,a,b)  for(int i=a;i>=b;i--)
#define lb          lower_bound
#define ub          upper_bound

#define bg(i)       i.begin()
#define fset(it,s)   for(auto it = s.begin(); it != s.end(); it++)
 
#define track(x)                 cerr<<#x<<": "<<x<<endl
#define track2(x, y)             cerr<<#x<<": "<<x<<" | "<<#y<<": "<<y<<endl
#define track3(x, y, z)          cerr<<#x<<":" <<x<<" | "<<#y<<": "<<y<<" | "<<#z<<": "<<z<<endl
#define track4(a, b, c, d)       cerr<<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<endl
 
#define ed(i)       i.end()
#define mem(a)	    memset(a, 0, sizeof(a))

#define MOD         1000000007
ll mult(ll a,ll b, ll p=MOD){return ((a%p)*(b%p))%p;}
ll add(ll a, ll b, ll p=MOD){return (a + b + p)%p;}
ll fpow(ll n, ll k, ll p = MOD) {ll r = 1; for (; k; k >>= 1LL) {if (k & 1LL) r = mult(r,n,p); n = mult(n,n,p);} return r;}
ll inv(ll a, ll p = MOD) {return fpow(a, p - 2, p);}
void self_max(int &a, int b) {a = max(a, b); }
void self_min(int &a, int b) {a = min(a, b); }
void self_add(int &a, int b, int p = MOD) { a += b; if(a >= p) a -= p;}
void self_sub(int &a, int b, int p = MOD) { a -= b; if(a < 0) a += p;}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
const int INF = 1e9 + 5;
#define N	    	400001


int __gcd(int a, int b) 
{ 
    if (a == 0) 
        return b; 
    return __gcd(b % a, a); 
}

void solve(){
    int n;
    cin>>n;
    int a[n];
    vi before(n), after(n);
    rep(i, 0, n) {
        cin>>a[i];
        if(i == 0)
            before[i] = a[i];
        else
            before[i] = __gcd(a[i], before[i-1]);
    }
    rev(i, n-1, 0) 
        if(i == n-1)
            after[i] = a[i];
        else
            after[i] = __gcd(a[i], after[i+1]);
    int ans = 0;
    rep(i, 1, n-1) {
        ans = max(ans, __gcd(before[i-1], after[i+1]));
    }
    cout<<max(ans, (int)max(before[n-2], after[1]))<<endl;
}

int main() {
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(20);
	cin.tie(0);
	cout.tie(0);
	int t = 1;
//	cin>>t;
	while(t--){
		solve();
	}
}




Compiler output:
a.cc: In function 'void solve()':
a.cc:75:18: error: no matching function for call to 'max(int&, long long int)'
   75 |         ans = max(ans, __gcd(before[i-1], after[i+1]));
      |               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:1:
/usr/include/c++/14/bits/stl_algobase.h:257:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::max(const _Tp&, const _Tp&)'
  257 |     max(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:257:5: note:   template argument deduction/substitution failed:
a.cc:75:18: note:   deduced conflicting types for parameter 'const _Tp' ('int' and 'long long int')
   75 |         ans = max(ans, __gcd(before[i-1], after[i+1]));
      |               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::max(const _Tp&, const _Tp&, _Compare)'
  303 |     max(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:303:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5706:5: note: candidate: 'template<class _Tp> constexpr _Tp std::max(initializer_list<_Tp>)'
 5706 |     max(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5706:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5716:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::max(initializer_list<_Tp>, _Compare)'
 5716 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5716:5: note:   template argument deduction/substitution failed:
a.cc:75:18: note:   mismatched types 'std::initializer_list<_Tp>' and 'int'
   75 |         ans = max(ans, __gcd(before[i-1], after[i+1]));
      |               ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~