1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
//mt19937 mrand(random_device{}());
const ll mod=1000000007;
//int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
int gcd(int a,int b) { return b?gcd(b,a%b):a;}
// head

const int N=1e5+5;

#define INF 0x3f3f3f3f

template<class T> inline void read(T &x) {
    x=0; int c=getchar(),f=1;
    for (;!isdigit(c);c=getchar()) if (c==45) f=-1;
    for (;isdigit(c);c=getchar()) (x*=10)+=f*(c-'0');
}

int a[N],s[N];

int main() {
    int n;
    scanf("%d",&n);
    rep(i,0,n) scanf("%d",&a[i]);
    auto check=[&](int k)->bool{
        int curr=0;
        rep(i,0,n) {
            s[i]=a[i]-curr;
            if (s[i]<0) return false;
            curr+=s[i];
            if (i-k+1>=0) curr-=s[i-k+1];
        }
        rep(i,max(0,n-k+1),n) if (s[i]!=0) return false;
        return true;
    };
    int lo=1,hi=n,ans=1;
    while (lo<=hi) {
        int md=(lo+hi)>>1;
        if (check(md)) {
            ans=md;
            lo=md+1;
        } else hi=md-1;
    }
    printf("%d\n",ans);
}