#include <iostream> #include <algorithm> #include <vector> #include <queue> #include <set> #include <string> #include <cmath> #include <map> #include <unordered_map> #include <fstream> #include <iomanip> #include <iterator> #include <stack> using namespace std; using ll = long long; int a[2000000]; int b[2000000]; int erk = 1, n, mod = 1000000007; ll k; ll BinPow(ll a, int x) { if (x == 0) return 1; if (x % 2 == 0) { return BinPow((a * a) % mod, x / 2); } return(a * BinPow(a, x - 1)) % mod; } int Bin = BinPow(2, mod - 2); void rec(int p, ll qan, ll qan1, ll ind, ll erk) { if (p == n) { cout << ind; exit(0); } if ((qan + 1) / 2 != (qan1 + 1) / 2) { rec(p + 1, (qan + 1) / 2, (qan1 + 1) / 2, (mod + ind - erk)%mod, (erk * Bin) % mod); } else { rec(p + 1, qan / 2, qan1 / 2, ind, (erk * Bin) % mod); } } int main() { ios_base::sync_with_stdio(false); cin.tie(0); int i, j, erk = 1; cin >> n >> k; for ( i = 0; i < n - 1; i++) { erk = (erk * 2) % mod; } rec(0, k, k - 1, (erk * 2)%mod, erk); return 0; }

rack.cpp: In function 'int main()':
rack.cpp:51:12: warning: unused variable 'j' [-Wunused-variable]
   51 |     int i, j, erk = 1;
      |            ^