Submission #447483

#	Time	Username	Problem	Language	Result	Execution time	Memory
447483		ak2006	Ice Hockey World Championship (CEOI15_bobek)	C++14	100 / 100	527 ms	8652 KiB

bobek

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vb = vector<bool>;
using vvb = vector<vb>;
using vi = vector<int>;
using vvi = vector<vi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vc = vector<char>;
using vvc = vector<vc>;
using vs = vector<string>;
const ll mod = 1e9 + 7,inf = 1e18;
#define pb push_back
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
void setIO()
{
    fast;
}
int n = 40;
ll m;
vl a(n);
int main()
{
    setIO();
    cin>>n>>m;
    for (int i = 0;i<n;i++)cin>>a[i];
    int pivot = n/2;
    //generate all subsets of the first pivot integers (0 to pivot - 1)
    //generate all subsets of the remaining n - pivot integers (pivot to n - 1)
    //sort the first subset and for each number in the second subset, find
    //the last position in the first subset such that the number there + the current element in the
    //subset is <= m
    //if sum + X > m
    //then X > m - sum
    vl firstSubset;
    for (int mask = 0;mask<(1<<pivot);mask++){
        ll sum = 0;
        for (int i = 0;i<pivot;i++)
            if (mask & (1<<i))sum += a[i];
        firstSubset.pb(sum);
    }
    sort(firstSubset.begin(),firstSubset.end());
    ll cnt = 0;
    for (int mask = 0;mask<(1<<(n - pivot));mask++){
        ll sum = 0;
        for (int i = pivot;i<n;i++)
            if (mask & (1<<(i - pivot)))sum += a[i];
        cnt += upper_bound(firstSubset.begin(),firstSubset.end(),m - sum) - firstSubset.begin();
    }
    cout<<cnt;
    return 0;
}

• 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