Submission #587420

#	Time	Username	Problem	Language	Result	Execution time	Memory
587420		welleyth	Binary Subsequences (info1cup17_binary)	C++17	0 / 100	1 ms	340 KiB

binary

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;

#define int long long
#define mp make_pair
#define pb push_back

#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("avx2")

constexpr long long INF = (long long)4e9;
constexpr int N = (int)5e5 + 111;
constexpr int md = (int)1e9 + 7;
constexpr int mdPower = (int)1e9+7 - 1;
constexpr int P = (int)998244343;

//typedef __int128 _uint;
typedef long long ll;

mt19937_64 rnd(time(nullptr));

void add(int& a,int b){
    a += b; if(a >= md) a -= md;
}
void sub(int& a,int b){
    a -= b; while(a < 0) a += md;
}

int bpow(int a,int b){
    if(b == 0)
        return 1;
    if(b % 2 == 0){
        int t = bpow(a,b>>1);
        return 1ll*t*t%md;
    }
    return 1ll * a*bpow(a,b-1) % md;
}

int inv(int a){
    return bpow(a,md-2);
}

//int fac[N],invfac[N];
//
//void init(){
//    fac[0] = 1;
//    for(int i = 1; i < N; i++){
//        fac[i] = (fac[i-1] * i) % md;
//    }
//    invfac[N-1] = inv(fac[N-1]);
//    for(int i = N-2; i >= 0; i--){
//        invfac[i] = (invfac[i+1] * (i+1))%md;
//    }
//    return;
//}
//
//int C(int n,int k){
//    if(k > n)
//        return 0;
//    return fac[n] * invfac[k] % md * invfac[n-k] % md;
//}
//
//int A(int n,int k){
//    if(k > n)
//        return 0;
//    return fac[n] * invfac[n-k] % md;
//}

struct DSU{ /// currently there is dsu on array
    vector<int> parent;
    vector<int> sz;
    vector<int> deep;
    DSU(){}
    DSU(int n){
        n = n+10;
        parent.resize(n);
        sz.resize(n);
        deep.resize(n);
        for(int i = 0; i < n; i++)
            parent[i] = i, sz[i] = 1,deep[i] = 0;
    }
    int get(int x){
        return parent[x] == x ? x : parent[x] = get(parent[x]);
    }
    void union_sets(int a,int b){
        a = get(a), b = get(b);
        if(a == b)
            return;
//        #warning DSU is written badly
        if(deep[b] > deep[a])
            swap(a,b);
        parent[a] = b;
        deep[b] = max(deep[b],deep[a]+1);
        sz[b] += sz[a];
        return;
    }
    bool connected(int a,int b){
        return get(a) == get(b);
    }
};

void solve(){
    int n;
    cin >> n;

    cout << bpow(2,n-1) << "\n";
    cout << "-1\n";

    return;
}

signed main(){
    ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
    int tests = 1;
    cin >> tests;
    for(int test = 1; test <= tests; test++){
//        cerr << "test = " << test << "\n";
        solve();
    }
    return 0;
}
/**
(a + b) ^ (a + c) ^ (b + c) =
a + b = (a^b + (a&b)<<1)
**/

• Subtask 1: 0 / 43
• Subtask 2: 0 / 39
• Subtask 3: 0 / 18