Submission #1118995

#	Time	Username	Problem	Language	Result	Execution time	Memory
1118995		Dan4Life	Rack (eJOI19_rack)	C++17	40 / 100	1 ms	504 KiB

rack

#include <bits/stdc++.h>
using namespace std;
#define int long long
int n, k;
const int MOD = (int)1e9+7;
int poww(int a, int b){
	if(!b) return 1;
	int x = poww(a,b/2);
	x*=x, x%=MOD;
	if(b&1) x*=a, x%=MOD;
	return x;
}
int32_t main(){
	cin >> n >> k;
	int l = 1, r = poww(2,n);
	while(n--){
		int mid = l+r;
		if(mid%2) mid--;
		mid *= poww(2,MOD-2); mid%=MOD;
		if(k%2) k/=2, k++, r = mid;
		else k/=2, l=(mid+1)%MOD;
	}
	cout << l << "\n";
}

• Subtask 1: 20 / 20
• Subtask 2: 20 / 20
• Subtask 3: 0 / 60