oj.uz

답안 #21285

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
21285 2017-04-12T10:06:20 Z suzy 능력 (kriii4_S) C++11
100 / 100
 1533 ms 392052 KB 
#include <stdio.h>
#include <string.h>

typedef long long lli;

#define MOD 1000000007LL

lli p[5001], q[5001], d[5001], fac[5001];
int n;
lli r[5001][5001], rd[5001][5001];

lli pw(lli n, lli x) {
    if(x==0) return 1;
    if(x%2) return n*pw(n,x-1)%MOD;
    else { lli ret=pw(n,x/2); return ret*ret%MOD; }
}

int main() {
    memset(rd,-1,sizeof(rd));
    fac[0]=1;
    for(lli i=1;i<=5000;i++)
        fac[i]=fac[i-1]*i%MOD;
    scanf("%d",&n);
    for(int i=1;i<=n;i++) {
        scanf("%lld %lld",&p[i],&d[i]);
        q[i]=(1000000000-p[i])*pw(1000000000,MOD-2)%MOD;
        p[i]=p[i]*pw(1000000000,MOD-2)%MOD;
    }
    for(int i=0;i<=5000;i++) {
        r[0][i]=1;
    }
    for(int j=1;j<=n;j++) {
        for(int i=1;i<=n;i++)
            r[i][j]=(r[i-1][j-1]*q[j]%MOD+r[i][j-1])%MOD;
    }
    for(int i=0;i<=n;i++) {
        rd[0][i]=1;
    }
    for(int i=1;i<=n;i++) {
        for(int j=1;j<=n;j++) {
            rd[i][j]=(r[i][n]-rd[i-1][j]*q[j]%MOD+MOD)%MOD;
        }
    }
    lli res=0;
    for(int i=1;i<=n;i++) {
        lli mult=p[i]*d[i]%MOD, add=0;
        for(int j=0;j<=n-1;j++) {
            lli ff=fac[j]*fac[n-j-1]%MOD;
            add+=ff*rd[j][i]%MOD;
            add%=MOD;
        }
        res+=add*mult%MOD; res%=MOD;
    }
    res*=pw(fac[n],MOD-2); res%=MOD;
    printf("%lld\n",res);
    return 0;
}

Compilation message

S.cpp: In function 'int main()':
S.cpp:23:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
                   ^
S.cpp:25:39: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%lld %lld",&p[i],&d[i]);
                                       ^

Subtask #1
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 26 ms 392052 KB Output is correct
2 Correct 16 ms 392052 KB Output is correct
3 Correct 6 ms 392052 KB Output is correct
4 Correct 13 ms 392052 KB Output is correct
5 Correct 6 ms 392052 KB Output is correct
6 Correct 6 ms 392052 KB Output is correct
7 Correct 9 ms 392052 KB Output is correct
8 Correct 16 ms 392052 KB Output is correct
9 Correct 16 ms 392052 KB Output is correct
10 Correct 6 ms 392052 KB Output is correct
11 Correct 16 ms 392052 KB Output is correct
12 Correct 13 ms 392052 KB Output is correct
13 Correct 16 ms 392052 KB Output is correct
14 Correct 16 ms 392052 KB Output is correct
15 Correct 13 ms 392052 KB Output is correct
16 Correct 29 ms 392052 KB Output is correct
17 Correct 19 ms 392052 KB Output is correct
18 Correct 19 ms 392052 KB Output is correct
19 Correct 6 ms 392052 KB Output is correct
20 Correct 13 ms 392052 KB Output is correct

Subtask #2
90.0 / 90.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1493 ms 392052 KB Output is correct
2 Correct 1503 ms 392052 KB Output is correct
3 Correct 1479 ms 392052 KB Output is correct
4 Correct 1489 ms 392052 KB Output is correct
5 Correct 1533 ms 392052 KB Output is correct
6 Correct 1533 ms 392052 KB Output is correct
7 Correct 1463 ms 392052 KB Output is correct
8 Correct 1509 ms 392052 KB Output is correct
9 Correct 1453 ms 392052 KB Output is correct
10 Correct 1506 ms 392052 KB Output is correct
11 Correct 1506 ms 392052 KB Output is correct
12 Correct 1463 ms 392052 KB Output is correct
13 Correct 1446 ms 392052 KB Output is correct
14 Correct 1466 ms 392052 KB Output is correct
15 Correct 1429 ms 392052 KB Output is correct
16 Correct 1473 ms 392052 KB Output is correct
17 Correct 1383 ms 392052 KB Output is correct
18 Correct 1459 ms 392052 KB Output is correct
19 Correct 1393 ms 392052 KB Output is correct
20 Correct 1416 ms 392052 KB Output is correct