Submission #972109

#	Time	Username	Problem	Language	Result	Execution time	Memory
972109		sleepntsheep	Rack (eJOI19_rack)	C11	100 / 100	29 ms	34728 KiB

rack

#include <stdio.h>

#define MOD 1000000007ll
#define N 1000005
int p2[N];
long long n, k;

long long a(long long k,long long l,long long r,int d)
{
    if(d==n)return 1;
    if(k&1) return a((k+1)/2, l, r-1, d+1) % MOD;
    else return (a(k/2, l+1, r, d+1) + p2[n-1-d]) % MOD;
}

int main()
{
    p2[0]=1;for(int i=1;i<N;++i)p2[i]=(p2[i-1]<<1)%MOD;
    scanf("%lld%lld",&n,&k);
    printf("%lld",a(k,0,n,0));
}

Compilation message (stderr)

rack.c: In function 'main':
rack.c:18:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |     scanf("%lld%lld",&n,&k);
      |     ^~~~~~~~~~~~~~~~~~~~~~~

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