//Never stop trying
/*#pragma GCC target ("avx2")
#pragma GCC optimize ("Ofast")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")*/
#include "bits/stdc++.h"
#ifndef LOCAL
#include "gap.h"
#endif
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
typedef long long ll;
typedef string str;
typedef double db;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second
typedef vector<int> vi;
typedef vector<pi> vpi;
typedef vector<str> vs;
typedef vector<ld> vd;
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
const int MOD = 1e9 + 7; //998244353
const ll INF = 1e18;
const int MX = 2e5 + 10;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up
template<class T> using V = vector<T>;
template<class T> bool ckmin(T& a, const T& b) { return a > b ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
//constexpr int log2(int x) { return 31 - __builtin_clz(x); } // floor(log2(x))
mt19937 rng(chrono::system_clock::now().time_since_epoch().count());
//mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
ll random(ll a, ll b){
return a + rng() % (b - a + 1);
}
#ifndef LOCAL
#define cerr if(false) cerr
#endif
#define dbg(x) cerr << #x << " : " << x << endl;
#define dbgs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl;
#define dbgv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
#define here() cerr << "here" << endl;
void IO() {
#ifdef LOCAL
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
}
V<ll> v(MX,INF+1);
#ifdef LOCAL
void MinMax(ll l, ll r, ll *x, ll *y){
auto it=lower_bound(all(v),l)-v.begin();
auto itr=upper_bound(all(v),r)-v.begin(); itr--;
if(it>itr) *x=-1ll,*y=-1ll;
else *x=v[it],*y=v[itr];
}
#endif
ll fir,last;
bool check(ll x){
x--;
ll l=fir;
while(l+x<=last){
ll v,vv;
MinMax(l,l+x,&v,&vv);
if(v!=vv) l=vv;
else return true;
}
return false;
}
ll findGap(int T, int N){
if(T==1){
V<ll> a(N);
ll l,r,mn=0,mx=INF;
FOR(i,0,(N+1)/2){
MinMax(mn,mx,&l,&r);
a[i]=l,a[N-i-1]=r;
mn=l+1,mx=r-1;
}
ll ans=1;
FOR(i,0,N-1) ckmax(ans,a[i+1]-a[i]);
return ans;
}
else{
MinMax(0,INF,&fir,&last);
V<ll> vec;
ll B=(last-fir)/(N-1);
ll l=fir;
while(l<=last){
ll v,vv;
MinMax(l,min(last,l+B),&v,&vv);
if(v!=-1){ vec.pb(v); vec.pb(vv); }
l+=B+1;
}
ll ans=B;
FOR(i,0,sz(vec)-1){
ckmax(ans,vec[i+1]-vec[i]);
}
return ans;
}
return 1;
}
#ifdef LOCAL
int main() {
boost; IO();
int N; cin>>N;
FOR(i,0,N) cin>>v[i];
cout << findGap(2,N) << endl;
return 0;
}
#endif
/* Careful!!!
.Array bounds
.Infinite loops
.Uninitialized variables / empty containers
.Multisets are shit
Some insights:
.Binary search
.Graph representation
.Write brute force code
.Change your approach
*/
