Submission #407224

#	Time	Username	Problem	Language	Result	Execution time	Memory
407224		luka1234	Rack (eJOI19_rack)	C++14	100 / 100	6 ms	204 KiB

rack

#include <bits/stdc++.h>
#define ll long long
#define ff first
#define ss second
using namespace std;  
ll p=1000000007;
ll logpow(ll v,ll e){
	if(e==0)
	   return 1;
	else{
		if(e%2==0){
			ll ans=logpow(v,e/2);
			ans%=p;
			ans=ans*ans;
			ans%=p;
			return ans;
		}
		else{
			ll ans=logpow(v,e/2);
			ans%=p;
			ans=ans*ans;
			ans%=p;
			ans*=v;
			ans%=p;
			return ans;
		}
	}
}
int main(){
    ll n,m;
    cin>>n>>m;
    ll v=1,cnt=0;
    while(cnt!=n){
    	if(m%2==1)
           v=2*v;
        else
           v=2*v+1;
        v%=p;
        if(m%2==0)
           m=m/2;
        else
           m=m/2+1;
        cnt++;
	}
	ll pow=logpow(2,n)-1;
	pow%=p;
	ll ans=v-pow;
	if(ans<0)
	   ans=p-abs(ans);
	cout<<ans;
    return 0;
}

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