Submission #464356

#	Time	Username	Problem	Language	Result	Execution time	Memory
464356		tengiz05	Rack (eJOI19_rack)	C++17	100 / 100	19 ms	15436 KiB

rack

#include <bits/stdc++.h>

using i64 = long long;

constexpr int P = 1000000007;

constexpr i64 inf = 2e18;

int norm(int x) {
    if (x < 0) x += P;
    if (x >= P) x -= P;
    return x;
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    i64 n, k;
    std::cin >> n >> k;
    k--;
    
    std::vector<i64> mpw(n + 1, 1), pw(n + 1, 1);
    for (int i = 1; i <= n; i++) {
        mpw[i] = mpw[i - 1] * 2 % P;
        pw[i] = std::min(pw[i - 1] * 2, inf);
    }
    
    int ans = 0;
    for (int i = 0; i < n; i++) {
        if (k >= pw[n - i - 1]) {
            ans = norm(ans + mpw[i]);
            k -= pw[n - i - 1];
        }
    }
    
    std::cout << norm(ans + 1) << "\n";
    
    return 0;
}


/*




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*/

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