Submission #1157031

#	Time	Username	Problem	Language	Result	Execution time	Memory
1157031		dosts	Ice Hockey World Championship (CEOI15_bobek)	C++20	100 / 100	632 ms	52764 KiB

bobek

#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
using namespace std;
#define int long long
#define pii pair<int,int>
#define ff first
#define ss second
#define sp << " " <<    
#define all(cont) cont.begin(),cont.end()
#define vi vector<int>

const int inf = 1e17,N = 5e5+1,MOD =  998244353;

void solve() {  
    //how many subset sums < x 
    //N <= 40
    int n,x;
    cin >> n >> x;
    vi a(n+1);
    for (int i=1;i<=n;i++) cin >> a[i];
    int lim1 = (1<<(n/2));
    int lim2 = (1<<(n-n/2));
    unordered_map<int,int> mp;
    vi st;
    for (int i = 0;i<lim1;i++) {
        int sm = 0;
        for (int j = 0;j<n/2;j++) {
            if (i&(1<<j)) sm+=a[j+1];
        }
        if (!mp[sm]) st.push_back(sm);
        mp[sm]++;
    }
    sort(all(st));
    int sm = 0;
    for (auto it : st) {
        sm+=mp[it];
        mp[it]=sm;
    }
    int ans = 0;
    for (int i = 0;i<lim2;i++) {
        int sm = 0;
        for (int j = 0;j<(n-n/2);j++) {
            if (i&(1<<j)) sm+=a[n/2+j+1];
        }
        auto it = upper_bound(all(st),x-sm);
        if (it == st.begin()) continue;
        int lkey = *(prev(it));
        ans+=mp[lkey];
    }
    cout << ans << '\n';
}


int32_t main() { 
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    #ifdef Dodi 
        freopen("in.txt","r",stdin);
        freopen("out.txt","w",stdout);
    #endif
    int t = 1;
    //cin >> t;
    while (t --> 0) solve();
}

• 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