Submission #19663

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
19663	2016-02-25T04:20:23 Z	tonyjjw	괄호 (kriii4_R)	C++14	8 / 100	294 ms	16904 KB

R

//*
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<algorithm>
#include<vector>
#define all(A) (A).begin(), (A).end()

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;

const int MN = 1000000+10;
const ll mod = 1000000007;

ll fact[MN];
ll inv[MN];

ll pow(ll a,ll p){
	ll r=1;
	while(p>0){
		if(p&1)r=r*a%mod;
		a=a*a%mod;
		p>>=1;
	}
	return r;
}

ll comb(ll n,ll r){
	return fact[n]*inv[r]%mod*inv[n-r]%mod;
}
ll inverse(ll a){
	return pow(a,mod-2);
}

int main(){
	int N,K;
	scanf("%d%d",&N,&K);
	fact[0]=1;
	for(int i=1;i<MN;i++){
		fact[i]=fact[i-1]*i%mod;
	}
	for(int i=0;i<MN;i++){
		inv[i]=inverse(fact[i]);
	}
	ll ans=0;
	for(int i=0;2*i<=N;i++){
		ll v;
		if(i==0){
			v=1;
		}
		else{
			v=comb(N,i)-comb(N,i-1);
		}
		v*=pow(K,N-i);
		v%=mod;
		ans+=v;
		ans%=mod;
	}
	if(ans<0)ans+=mod;
	printf("%lld\n",ans);
	return 0;
}
//*/

Subtask #1

8.0 / 8.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	266 ms	16904 KB	Output is correct
2	Correct	260 ms	16904 KB	Output is correct
3	Correct	281 ms	16904 KB	Output is correct
4	Correct	284 ms	16904 KB	Output is correct
5	Correct	289 ms	16904 KB	Output is correct
6	Correct	271 ms	16904 KB	Output is correct
7	Correct	277 ms	16904 KB	Output is correct
8	Correct	267 ms	16904 KB	Output is correct
9	Correct	260 ms	16904 KB	Output is correct
10	Correct	259 ms	16904 KB	Output is correct
11	Correct	260 ms	16904 KB	Output is correct
12	Correct	282 ms	16904 KB	Output is correct
13	Correct	280 ms	16904 KB	Output is correct
14	Correct	265 ms	16904 KB	Output is correct
15	Correct	262 ms	16904 KB	Output is correct
16	Correct	262 ms	16904 KB	Output is correct
17	Correct	289 ms	16904 KB	Output is correct
18	Correct	284 ms	16904 KB	Output is correct
19	Correct	291 ms	16904 KB	Output is correct
20	Correct	294 ms	16904 KB	Output is correct

Subtask #2

0.0 / 92.0

#	Verdict	Execution time	Memory	Grader output
1	Incorrect	271 ms	16904 KB	Output isn't correct
2	Halted	0 ms	0 KB	-