Submission #957441

#	Time	Username	Problem	Language	Result	Execution time	Memory
957441		rahidilbayramli	Rack (eJOI19_rack)	C++17	100 / 100	2 ms	460 KiB

rack

#pragma GCC optimize("-O3")
#include<bits/stdc++.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define vl vector<ll>
#define vi vector<int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define pb push_back
#define p_b pop_back
#define f first
#define s second
using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
const ll mod = 1e9+7;
ll binpow(ll a, ll b)
{
    ll res = 1;
    while(b)
    {
        if(b & 1)
            res = res * a % mod;
        a = a * a % mod;
        b >>= 1;
    }
    return res;
}
void solve()
{
    ll n, k, i, ans = 1, e, x;
    cin >> n >> k;
    for(i = n - 1; i >= 0; i--)
    {
        if(k % 2 == 0)
        {
            ans += binpow(2, i);
            ans %= mod;
        }
        k = (k + 1) / 2;
    }
    cout << ans << "\n";
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    ll tests = 1;
    //cin >> tests;
    while(tests--)
    {
        solve();
    }
}

Compilation message (stderr)

rack.cpp: In function 'void solve()':
rack.cpp:35:26: warning: unused variable 'e' [-Wunused-variable]
   35 |     ll n, k, i, ans = 1, e, x;
      |                          ^
rack.cpp:35:29: warning: unused variable 'x' [-Wunused-variable]
   35 |     ll n, k, i, ans = 1, e, x;
      |                             ^

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 60 / 60