Submission #19393

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
19393	2016-02-24T11:11:31 Z	bshnet	Σ (kriii4_P2)	C++14	100 / 100	16 ms	1720 KB

P2

#include <iostream>
#include <vector>

#define MOD (1000000007)

using namespace std;

int pow(int64_t a, int64_t x) {
	int64_t sq[64];
	int ans = 1;

	sq[0] = (a % MOD);
	for(int i = 1; i <= 64; ++i) {
		if(x & 0x01)
			ans = (ans * sq[i-1]) % MOD;

		x >>= 1;
		if(!x)
			break;

		sq[i] = (sq[i-1] * sq[i-1]) % MOD;
	}

	return ans;
}

int expect(vector<int> &ni, vector<int> &si) {
	int n = ni.size();
	int ans = 0;
	for(int i = 0; i < n; ++i) {
		int64_t e = ((int64_t)si[i] * pow(ni[i], MOD - 2)) % MOD;
		ans = (ans + e) % MOD;
	}
	return ans;
}

int main(void) {
	int M;
	cin >> M;

	vector<int> Ni(M), Si(M);
	for(int i = 0; i < M; ++i) {
		cin >> Ni[i] >> Si[i];
	}

	cout << expect(Ni, Si) << endl;

	return 0;
}

Subtask #1

100.0 / 100.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	12 ms	1720 KB	Output is correct
2	Correct	16 ms	1720 KB	Output is correct
3	Correct	16 ms	1720 KB	Output is correct
4	Correct	10 ms	1720 KB	Output is correct
5	Correct	16 ms	1720 KB	Output is correct
6	Correct	12 ms	1720 KB	Output is correct
7	Correct	11 ms	1720 KB	Output is correct
8	Correct	12 ms	1720 KB	Output is correct
9	Correct	15 ms	1720 KB	Output is correct
10	Correct	14 ms	1720 KB	Output is correct
11	Correct	14 ms	1720 KB	Output is correct
12	Correct	14 ms	1720 KB	Output is correct
13	Correct	14 ms	1720 KB	Output is correct
14	Correct	15 ms	1720 KB	Output is correct
15	Correct	11 ms	1720 KB	Output is correct
16	Correct	15 ms	1720 KB	Output is correct
17	Correct	15 ms	1720 KB	Output is correct
18	Correct	11 ms	1720 KB	Output is correct
19	Correct	12 ms	1720 KB	Output is correct
20	Correct	16 ms	1720 KB	Output is correct