| # |
Submission time |
Handle |
Problem |
Language |
Result |
Execution time |
Memory |
| 20001 |
2016-02-25T08:20:58 Z |
tonyjjw |
카드 (kriii4_Z) |
C++14 |
|
9 ms |
72288 KB |
//*
#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;
cout<<ans;
return 0;
}
//*/
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
9 ms |
72288 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Halted |
0 ms |
0 KB |
- |
