Submission #1837261

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Source Code Expand

#define _CRT_SECURE_NO_WARNINGS
#include <vector>
#include <iostream>
#include <string.h>
#include <string>
#include <algorithm>
using namespace std;

typedef double LD;
typedef long long LL;
typedef pair<int, int> PII;
#define MP make_pair
#define PB push_back
#define FOR(i,a,b) for(int i = (a); i < (b); ++i)
#define RFOR(i,b,a) for(int i = (b) - 1; i >= (a); --i)
#define REP(i, t) FOR(i,0,t)
#define ALL(a) a.begin(), a.end()
#define SZ(a) (int)((a).size())

const LL MOD = 1000000007;
const int INF = 1e9;
const int MAXN = 100007;
const LD EPS = 1e-7;

int n, A[MAXN];

bool possible()
{
	LL s = 0, c;
	REP(i, n) s += A[i];
	if ((2 * s) % (n * (n + 1LL))) return false;
	c = (2 * s) / (n * (n + 1LL));
	REP(i, n)
	{
		if (c + A[i] - A[i + 1] < 0) return false;
		if ((c + A[i] - A[i + 1]) % n) return false;
	}
	return true;
}

int main()
{
	ios_base::sync_with_stdio(0);
	//freopen("In.txt", "r", stdin);
	cin >> n;
	REP(i, n) cin >> A[i];
	A[n] = A[0];
	if (possible()) cout << "YES";
	else cout << "NO";
	//cout << endl; system("pause");
	return 0;
}

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