oj.uz

Submission #20033

# Submission time Handle Problem Language Result Execution time Memory
20033 2016-02-25T08:45:47 Z suzy 괄호 (kriii4_R) C++
0 / 100
 392 ms 16708 KB 
#include <stdio.h>

#define MOD 1000000007

typedef long long lli;

lli f[1000001];
lli inv[1000001];

lli p(lli a, lli x) {
	if(x==0) return 1;
	if(x%2) return a*p(a,x-1)%MOD;
	else { lli m=p(a,x/2); return m*m%MOD; }
}

lli C(lli k) {
	lli ret=f[2*k]*inv[k]%MOD;
	return ret*inv[k+1]%MOD;
}

int main() {
	int n, k;
	f[0]=f[1]=1;
	for(lli i=2;i<=1000000;i++)
		f[i]=f[i-1]*i%MOD;
	for(lli i=0;i<=1000000;i++)
		inv[i]=p(f[i],MOD-2);
	scanf("%d %d",&n,&k);
	lli res=0, t=1;
	for(lli l=1;l<=n;l++) {
		if(l%2) t=(t*2-C((l-1)/2))%MOD;
		else t=t*2%MOD;
	}
	printf("%lld",t);
}

Subtask #1
0.0 / 8.0

# Verdict Execution time Memory Grader output
1 Incorrect 392 ms 16708 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0.0 / 92.0

# Verdict Execution time Memory Grader output
1 Halted 0 ms 0 KB -