Submission #87872

#	Time	Username	Problem	Language	Result	Execution time	Memory
87872		shoemakerjo	Ice Hockey World Championship (CEOI15_bobek)	C++14	100 / 100	463 ms	21688 KiB

bobek

#include <bits/stdc++.h>

using namespace std;
#define ll long long

int n;
ll m;

vector<ll> lsums, rsums;
ll ans = 0LL;

ll nums[50];

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);

	cin >> n >> m;
	for (int i = 1; i <= n; i++) {
		cin >> nums[i];
	}

	int mid = n/2;

	for (int mask = 0; mask < (1 << mid); mask++) {
		ll sum = 0LL;
		for (int i = 1; i <= mid; i++) {
			if (mask & (1 << (i-1))) {
				sum += nums[i];
			}
		}
		lsums.push_back(sum);
	}

	int onum = n-mid;
	for (int mask = 0; mask < (1 << onum); mask++) {
		ll sum = 0LL;

		for (int i = mid+1; i <= n; i++) {
			if (mask & (1 << (i - mid-1))) {
				sum += nums[i];
			}
		}
		rsums.push_back(sum);
	}

	sort(lsums.begin(), lsums.end());
	sort(rsums.begin(), rsums.end());

	for (ll val : lsums) {
		ans += upper_bound(rsums.begin(), rsums.end(), 
			m-val) - rsums.begin() + 0LL;
	}

	cout << ans << endl;



}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10