Submission #1296456

#	Time	Username	Problem	Language	Result	Execution time	Memory
1296456		herominhsteve	Ice Hockey World Championship (CEOI15_bobek)	C++20	100 / 100	400 ms	16852 KiB

bobek

#include <bits/stdc++.h>
#define el '\n'
#define FNAME "NAME"
#define allof(x) x.begin(),x.end()
#define allof1(x) x.begin()+1,x.end()
#define mset(x,n) memset(x,(n),sizeof(x))
using namespace std;
const long long MOD = (long long) 1e9 + 7;
template<class X,class Y> bool minimize(X &a,Y b){ if (a>b) {a=b; return true;} return false;}
template<class X,class Y> bool maximize(X &a,Y b){ if (a<b) {a=b; return true;} return false;}

void setup(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
	if (fopen(FNAME".inp","r")){
		freopen(FNAME".inp","r",stdin);
		freopen(FNAME".out","w",stdout);
	}
}

int n;
long long S;
vector<long long> a;

int ls,rs;
vector<long long> L,R;

void init(){
    cin>>n>>S;
    a.reserve(n);
    for (int i=0;i<n;i++){
        long long x; cin>>x;
        if (x <= S) a.push_back(x);
    }
    n = a.size();
    ls = n / 2;
    rs = n - ls;
    L.reserve(ls);
    for (int i=0;i<ls;i++) L.push_back(a[i]);
    R.reserve(rs);
    for (int i=ls;i<n;i++) R.push_back(a[i]);
}

vector<long long> build(const vector<long long> &a){
    int n = a.size();
    int MAXMASK = 1 << n;
    vector<long long> res; res.reserve(MAXMASK);

    for (int mask = 0; mask < MAXMASK; mask++){
        long long sum = 0;
        bool check = 1;
        for (int i=0;i<n;i++){
            if (mask & (1<<i)){
                if (sum <= S - a[i]){
                    sum += a[i];
                } else{
                    check = 0;
                    break;
                }
            }
        }
        if (!check) continue;
        res.push_back(sum);
    }
    return res;
}

void sol(){
    vector<long long> sumL = build(L);
    vector<long long> sumR = build(R);
    sort(allof(sumR));

    long long res = 0;

    for (long long x : sumL){
        vector<long long>::iterator it = upper_bound(allof(sumR),S - x);
        res += it - sumR.begin();
    }
    
    cout<<res;
}

int main(){
    setup();
    init();
    sol();
}

Compilation message (stderr)

bobek.cpp: In function 'void setup()':
bobek.cpp:16:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |                 freopen(FNAME".inp","r",stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
bobek.cpp:17:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |                 freopen(FNAME".out","w",stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• 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