답안 #19255

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
19255 2016-02-23T04:47:35 Z kaTkaHr 순열 (kriii4_T) C++14
8 / 100
2000 ms 1084 KB
#include <stdio.h>
#include<vector>
#include <algorithm>
#include <map>

using namespace std;

typedef long long ll;

const int MX = 105, MM = 1000000007;

ll rv(ll A){
    ll R = 1, B = MM-2;
    while(B){
        if( B&1 ) R = R * A % MM;
        A = A * A % MM; B /= 2;
    }
    return R;
}

struct frac{
    ll A, B;
		frac(ll A):A(A), B(1){}
    frac(ll a, ll b){
        A = (a%MM+MM) % MM;
        B = (b%MM+MM) % MM;
    }
    frac(){A = 0, B = 1;}
    frac operator+ (const frac &l)const{
        return frac((A * l.B + B * l.A) % MM, B * l.B % MM);
    }
    frac operator*(const frac &l)const{
        return frac(A*l.A % MM, B*l.B % MM);
    }
    frac operator/(const frac &l)const{
        return frac(A*l.B % MM, B*l.A % MM);
    }
    frac operator- (const frac &l)const{
        return frac((A*l.B - B*l.A%MM + MM) % MM, B*l.B % MM);
    }
    ll v(){ return A * rv(B) % MM; }
};

int main()
{
	int N, KK;
	scanf("%d%d", &N, &KK); 
	frac tot = 0;
	for(int K = KK+1; K <= N; K++){
		frac ans = 0, mul = 1;
		for(int i = 1; i <= N; i++){
			mul = mul * i;
		}
		for(int i = N; i >= 1; i--){
			mul = mul / i;
			ans = ans + mul * (N-i+1);
			mul = mul * (i-K);
		}
		ans = ans * K * (N-K+1);
		tot = ans + tot;
	}
	printf("%lld\n", tot.v());
}
# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 1084 KB Output is correct
2 Correct 0 ms 1084 KB Output is correct
3 Correct 0 ms 1084 KB Output is correct
4 Correct 0 ms 1084 KB Output is correct
5 Correct 0 ms 1084 KB Output is correct
6 Correct 0 ms 1084 KB Output is correct
7 Correct 0 ms 1084 KB Output is correct
8 Correct 0 ms 1084 KB Output is correct
9 Correct 0 ms 1084 KB Output is correct
10 Correct 0 ms 1084 KB Output is correct
11 Correct 0 ms 1084 KB Output is correct
12 Correct 0 ms 1084 KB Output is correct
13 Correct 0 ms 1084 KB Output is correct
14 Correct 0 ms 1084 KB Output is correct
15 Correct 0 ms 1084 KB Output is correct
16 Correct 5 ms 1084 KB Output is correct
17 Correct 28 ms 1084 KB Output is correct
18 Correct 9 ms 1084 KB Output is correct
19 Correct 18 ms 1084 KB Output is correct
20 Correct 23 ms 1084 KB Output is correct
21 Correct 32 ms 1084 KB Output is correct
22 Correct 0 ms 1084 KB Output is correct
23 Correct 0 ms 1084 KB Output is correct
24 Correct 39 ms 1084 KB Output is correct
25 Correct 5 ms 1084 KB Output is correct
26 Correct 47 ms 1084 KB Output is correct
27 Correct 0 ms 1084 KB Output is correct
28 Correct 89 ms 1084 KB Output is correct
29 Correct 87 ms 1084 KB Output is correct
30 Correct 32 ms 1084 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Execution timed out 2000 ms 1080 KB Program timed out
2 Halted 0 ms 0 KB -