Submission #161817

#	Time	Username	Problem	Language	Result	Execution time	Memory
161817		dantoh000	Ice Hockey World Championship (CEOI15_bobek)	C++14	100 / 100	456 ms	8700 KiB

bobek

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int main(){
    int n;
    ll m;
    scanf("%d%lld",&n,&m);
    ll a[n];
    for (int i = 0; i < n; i++) scanf("%lld",&a[i]);
    int ct = 0;
    int k = min(20,n-1);
    vector<ll> v(1<<k);
    for (int i = 0; i < (1<<k); i++){
        int cur = i;
        ll sum = 0;
        while (cur){
            int lsb = (cur)&(-cur);
            sum += a[__builtin_ctz(lsb)];
            cur -= lsb;
        }
        v[i] = sum;
    }
    sort(v.begin(),v.end());
    ll ans = 0;
    for (int i = 0; i < (1<<(n-k)); i++){
        int cur = i;
        ll sum = 0;
        while (cur){
            int lsb = (cur)&(-cur);
            sum += a[__builtin_ctz(lsb)+k];
            cur -= lsb;
        }
        //printf("%d %lld %lld\n",i,sum,(ll)(upper_bound(v.begin(),v.end(),m-sum)-v.begin()));
        ans += upper_bound(v.begin(),v.end(),m-sum)-v.begin();
    }
    printf("%lld\n",ans);
}

Compilation message (stderr)

bobek.cpp: In function 'int main()':
bobek.cpp:10:9: warning: unused variable 'ct' [-Wunused-variable]
     int ct = 0;
         ^~
bobek.cpp:7:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%lld",&n,&m);
     ~~~~~^~~~~~~~~~~~~~~~
bobek.cpp:9:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (int i = 0; i < n; i++) scanf("%lld",&a[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