Submission #37366

#	Time	Username	Problem	Language	Result	Execution time	Memory
37366		cheater2k	Ice Hockey World Championship (CEOI15_bobek)	C++14	100 / 100	253 ms	26792 KiB

bobek

#include <bits/stdc++.h>
using namespace std;

int n;
long long M;
long long a[44];
long long ans;
vector< long long > v1, v2;

void bt(int pos, int lim, long long sum, vector<long long> &v) {
	if (pos == lim) {
		v.push_back(sum); return;
	}
	bt(pos + 1, lim, sum, v);
	bt(pos + 1, lim, sum + a[pos], v);
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0);
	cin >> n >> M;
	for (int i = 0; i < n; ++i) cin >> a[i];
	bt(0, n / 2, 0, v1);
	bt(n / 2, n, 0, v2);

	sort(v1.begin(), v1.end());
	sort(v2.begin(), v2.end());

	int ptr = v2.size() - 1;
	for (int i = 0; i < v1.size(); ++i) {
		if (v1[i] > M) break;
		while(ptr >= 0 && v2[ptr] > M - v1[i]) --ptr;
		// [0...ptr]
		ans += ptr + 1;
	}

	printf("%lld\n", ans);
}

Compilation message (stderr)

bobek.cpp: In function 'int main()':
bobek.cpp:29:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < v1.size(); ++i) {
                    ^

• 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