Submission #981885

#	Time	Username	Problem	Language	Result	Execution time	Memory
981885		LOLOLO	Ice Hockey World Championship (CEOI15_bobek)	C++17	100 / 100	176 ms	22832 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 of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |  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