Pizzeria

#include <iostream>
#include <algorithm>
using namespace std;

typedef long long int ll;
const ll mod = 1000000007;

inline ll modadd(ll a, ll b) {
	return (a + b ) % mod;
}
inline ll modmul(ll a, ll b) {
	return (a*b) % mod;
}
inline ll modpow(ll b, ll e) {
	if (e == 0)
		return 1;
	if (e == 1)
		return b;
	if (e % 2 == 0) {
		ll p = modpow(b, e / 2);
		return modmul(p, p);
	}
	return modmul(modpow(b, e / 2), modpow(b, e / 2 + 1));
}
inline ll moddiv(ll a, ll b) {
	return modmul(a, modpow(b, mod - 2));
}

int main() {
	int n;
	cin >> n;

	ll sum = 0;
	for (int i = 0; i < n; i++) {
		int a;
		cin >> a;
		sum = modadd(sum, a);
	}

	ll mul = modpow(2, n-1);;

	cout << modmul(sum, mul);
}

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED