Submission #1093568

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Source Code Expand

#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<iostream>
#include<string>
#include<stack>
#include<queue>
#include<vector>
#include<tuple>
#include<map>
#include<set>
#include<algorithm>

#define rep(n) for(int i=0;i<n;i++)
#define repp(j, n) for(int j=0;j<n;j++)
#define reppp(i, m, n) for(int i=m;i<=n;i++)
#define all(c) c.begin(), c.end()
#define MOD 1000000007
#define MAX 1000000001
#define INF 1410065408
 
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
struct edge{int from, to; ll cost;};

signed main(){
	ll n, sum = 0, sun_n;
	cin >> n;
	ll a[n];
	rep(n){
		cin >> a[i];
		sum += a[i];
	}
	
	if(n==1){
		cout << "YES";
		return 0;
	}
	
	double sum_n = (double)sum / (n * (n+1) / 2);
	if(sum_n != (ll)sum_n){
		cout << "NO";
		return 0;
	}
	ll m = (ll)sum_n;

	ll diff = a[0] - a[n-1];
	ll d_count = m, i = 1;
	while(true){
		ll d = 0;
		ll diff_calc = m;
		while(diff != diff_calc && d_count >= 0){
			d++;
			diff_calc = diff_calc - 1 - (n-1) * d;
			d_count--;
		}
		if(diff != diff_calc){
			cout << "NO";
			return 0;
		}
		
		if(i >= n){
			break;
		}
		diff = a[i] - a[i-1];
		i++;
	}
	
	if(d_count == 0){
		cout << "YES";
		return 0;
	}else{
		cout << "NO";
		return 0;
	}
}

Submission Info

Judge Result