Submission #650269

#	Time	Username	Problem	Language	Result	Execution time	Memory
650269		Kenpar	Rack (eJOI19_rack)	C++17	100 / 100	13 ms	8148 KiB

rack

#include "bits/stdc++.h"
using namespace std;
 
#define ll long long
#define endl '\n'

const ll MOD = 1e9+7;
const ll INF = 1e16;
const int INT_INF = 1e9;
const ll MAX = 1e6+1;

ll pre[MAX + 5];
ll solve(ll cur, ll layer, ll ans){
	ans %= MOD;
	if(layer == -1){
		return ans;
	}

	if(cur % 2){
		return solve((cur + 1)/2, layer-1, ans);
	}

	return solve((cur + 1)/2, layer-1, ans + pre[layer]);
}
void solve(){
	ll a,b;
	cin>>a>>b;

	cout<<solve(b, a-1, 1);
}
 
 
int main()
{
	cin.tie(NULL);
	ios::sync_with_stdio(NULL);
	int t = 1;
 
	pre[0] = 1;

	for(int i = 1; i < MAX + 4; i++){
		pre[i] = (pre[i-1]*2)%MOD;
	}
	//cin >> t;
 
	while(t--){
		solve();
		cout<<endl;
	}
}

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