Submission #20005

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
20005	2016-02-25T08:22:46 Z	tonyjjw	카드 (kriii4_Z)	C++14	13 / 100	26 ms	72288 KB

Z

//*
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include <stdlib.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <numeric>
#include <functional>
#define MOD 1000000007
#define MAX 0x3f3f3f3f
#define MAX2 0x3f3f3f3f3f3f3f3fll
#define ERR 1e-10
#define mp make_pair
#define all(x) (x).begin(), (x).end()
#pragma warning(disable:4996)
using namespace std;

typedef long long ll;
typedef long double ldb;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<double, double> pdd;

ll mul_inv(ll a, ll b=MOD)
{
	ll b0=b, t, q;
	ll x0=0, x1=1;
	if(b == 1) return 1;
	while(a > 1)
	{
		q=a/b;
		t=b, b=a%b, a=t;
		t=x0, x0=x1-q*x0, x1=t;
	}
	if(x1 < 0) x1+=b0;
	return x1;
}


ll modpow(ll x, ll y)
{
    ll ans=1;
    while(y)
    {
        if(y%2) ans*=x, ans%=MOD;
        x*=x, x%=MOD, y/=2;
    }
    return ans;
}

ll N, L;
int a[5000];
ll ncr[3005][3005];

int main()
{
	int i, j, k;
	cin>>N>>L;
	for(i=0;i<=N;i++) for(j=0;j<=i;j++) ncr[i][j]=j==0||j==i?1:ncr[i-1][j-1]+ncr[i-1][j], ncr[i][j]%=MOD;
	for(i=0;i<N;i++) scanf("%d", &a[i]);
	int n=count(a, a+N, 1);
	ll ans=0;
	for(k=0;k<=n;k++)
	{
		ans+=modpow(-1, k)*modpow(N-k, L)%MOD*ncr[n][k];
		ans%=MOD;
	}
	ans*=mul_inv(modpow(N, L));
	ans%=MOD;
	ans+=MOD;
	ans%=MOD;
	cout<<ans;
	return 0;
}
//*/

Subtask #1

13.0 / 13.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	11 ms	72288 KB	Output is correct
2	Correct	9 ms	72288 KB	Output is correct
3	Correct	7 ms	72288 KB	Output is correct
4	Correct	14 ms	72288 KB	Output is correct
5	Correct	21 ms	72288 KB	Output is correct
6	Correct	8 ms	72288 KB	Output is correct
7	Correct	15 ms	72288 KB	Output is correct
8	Correct	9 ms	72288 KB	Output is correct
9	Correct	19 ms	72288 KB	Output is correct
10	Correct	11 ms	72288 KB	Output is correct
11	Correct	12 ms	72288 KB	Output is correct
12	Correct	16 ms	72288 KB	Output is correct
13	Correct	13 ms	72288 KB	Output is correct
14	Correct	19 ms	72288 KB	Output is correct
15	Correct	17 ms	72288 KB	Output is correct
16	Correct	4 ms	72288 KB	Output is correct
17	Correct	8 ms	72288 KB	Output is correct
18	Correct	12 ms	72288 KB	Output is correct
19	Correct	12 ms	72288 KB	Output is correct
20	Correct	21 ms	72288 KB	Output is correct
21	Correct	19 ms	72288 KB	Output is correct
22	Correct	17 ms	72288 KB	Output is correct
23	Correct	26 ms	72288 KB	Output is correct
24	Correct	11 ms	72288 KB	Output is correct
25	Correct	15 ms	72288 KB	Output is correct

Subtask #2

0.0 / 87.0

#	Verdict	Execution time	Memory	Grader output
1	Incorrect	12 ms	72288 KB	Output isn't correct
2	Halted	0 ms	0 KB	-