Submission #737096

#	Time	Username	Problem	Language	Result	Execution time	Memory
737096		tshabanov7	Rack (eJOI19_rack)	C++17	100 / 100	4 ms	4064 KiB

rack

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

constexpr int MOD = 1E9 + 7;

int add(int a, int b) {
    a += b;
    return a >= MOD ? a - MOD : a;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    ll k;
    cin >> k;
    k--;

    vector<int> pow2(n);
    pow2[0] = 1;
    for (int i = 0; i < n - 1; i++) {
        pow2[i + 1] = add(pow2[i], pow2[i]);
    }

    int ans = 0;
    while (k > 0) {
        ans = add(ans, (k % 2) * pow2[--n]);
        k /= 2;
    }

    cout << ans + 1 << "\n";

    return 0;
}

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