Submission #896988

#	Time	Username	Problem	Language	Result	Execution time	Memory
896988		Jawad_Akbar_JJ	Rack (eJOI19_rack)	C++17	40 / 100	7 ms	8564 KiB

rack

#include <iostream>
#include <vector>


using namespace std;
#define int long long
const int N = (1<<20) + 1;

int tp[N];
int mod = 1e9 + 7;

void solve(int n,int k){
	bool right = true;

	int ans = 0;
	for (int i=1;i<=n;i++){
		bool last = 1&k;
		k >>= 1;
		if (right and last)
			right = 0;
		else if (right)
			ans += tp[n - i];
		else if (!right and last)
			ans += tp[n - i];
	}	
	cout<<ans + !right<<endl;
}

signed main(){
	tp[0] = 1;
	for (int i=1;i<N;i++)
		tp[i] = tp[i-1] * 2 % mod;
	int n,k;
	cin>>n>>k;

	if (k==tp[n])
		cout<<tp[n]<<endl;
	else
		solve(n,k);
	return 0;
	for (int i=1;i<=8;i++)
		solve(3,i);

}

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