Submission #1214356

#	Time	Username	Problem	Language	Result	Execution time	Memory
1214356		badge881	Rack (eJOI19_rack)	C++20	100 / 100	7 ms	8004 KiB

rack

#include <bits/stdc++.h>

using namespace std;

using ll = long long;

const int MOD = 1e9 + 7;
const int MAX_N = 1e6;

ll pot[MAX_N];

int solve(int n, ll k)
{
    if (n == 0)
        return 1LL;
    if (k % 2 == 1)
        return solve(n - 1, (k + 1) / 2);
    int res = pot[n - 1] + solve(n - 1, k / 2);
    if (res >= MOD)
        res -= MOD;
    return res;
}

int main()
{
    int n;
    ll k;
    scanf("%d %lld", &n, &k);
    pot[0] = 1;
    for (int i = 1; i < n; i++)
    {
        pot[i] = 2 * pot[i - 1];
        if (pot[i] >= MOD)
            pot[i] -= MOD;
    }
    printf("%d\n", solve(n, k));
    return 0;
}

Compilation message (stderr)

rack.cpp: In function 'int main()':
rack.cpp:28:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |     scanf("%d %lld", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~

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