Submission #977076

#	Time	Username	Problem	Language	Result	Execution time	Memory
977076		SeenSiravit	Ice Hockey World Championship (CEOI15_bobek)	C++14	100 / 100	331 ms	22708 KiB

bobek

#include<bits/stdc++.h>
#define ll long long

using namespace std;

const int mxN = 40 + 5;

int n;
ll m;
ll a[mxN];

vector<ll> comb_l , comb_r;

void make_combination(){

    int mid = n/2;

    // comb_l [1 , mid]
    int lim = 1<<mid;

    for(int mask=0;mask<lim;mask++){
        ll sum = 0;
        for(int i=0;i<mid;i++){
            if((1<<i) & mask) sum += a[i];
            if(sum > m) break;
        }

        if(sum <= m) comb_l.push_back(sum);
    }

    sort(comb_l.begin() , comb_l.end());

    // comb_r
    lim = 1<<(n-mid);

    for(int mask=0;mask<lim;mask++){
        ll sum = 0;
        for(int i=0;i<(n-mid);i++){
            if((1<<i) & mask) sum += a[i+mid];
            if(sum>m) break;
        }

        if(sum <= m) comb_r.push_back(sum);
    }

    sort(comb_r.begin() , comb_r.end());
}

int main(){
    ios::sync_with_stdio(0),cin.tie(0);

    cin>> n >> m;

    for(int i=0;i<n;i++) cin>> a[i];

    make_combination();

    // for(auto val : comb_l) cout<< val << " ";
    // cout<< "\n";
    // for(auto val : comb_r) cout<< val << " ";
    // cout<< "\n";

    ll ans = 0;

    for(ll val : comb_r){
        int cnt = upper_bound(comb_l.begin() , comb_l.end() , m - val) - comb_l.begin();
        // cout<< cnt << " ";
        ans += cnt;
    }

    // cout<< "\n";

    cout<< ans;

    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