Submission #1513984

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Source Code Expand

#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9) + 7;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int N; cin >> N;
	vector<int> A(N); rep(i, 0, N) {
		cin >> A[i];
	}
	int sum = accumulate(all(A), 0LL);
	int p = N*(N + 1) / 2;
	if (sum%p != 0) {
		cout << "NO" << endl;
		return 0;
	}
	int k = sum / p;
	dump(k);
	vector<int> B(N), C(N);
	rep(i, 0, N) {
		B[i] = A[(i + 1) % N] - A[i];
	}
	dump(B);
	rep(i, 0, N) {
		if (B[i] > 0)continue;
		if ((k - B[i]) % N != 0) {
			cout << "NO" << endl;
			return 0;
		}
		C[i] = (k - B[i]) / N;
	}
	int sumc = accumulate(all(C), 0LL);
	dump(sumc);
	if (sumc != k) {
		cout << "NO" << endl;
		return 0;
	}
	cout << "YES" << endl;
	return 0;
}

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