#102325 (C++14) No.391 CODING WAR

• 問題: No.391 CODING WAR
• ユーザー: imulan
• 提出日時: 2016-07-09 00:06:03
• 言語: C++14 (gcc 13.3.0 + boost 1.87.0)
• 結果: AC
• 実行時間: 73 ms / 2,000 ms
• コード長: 1,493 bytes
• コンパイル時間: 1,423 ms
• コンパイル使用メモリ: 166,800 KB
• 実行使用メモリ: 5,248 KB
• 最終ジャッジ日時: 2024-10-13 07:42:43
• 合計ジャッジ時間: 2,635 ms
• ジャッジサーバーID （参考情報）: judge3 / judge5

ファイルパターン	結果
sample	AC * 4
other	AC * 16

ソースコード

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i,n) for(int (i)=0;(i)<(int)(n);++(i))
#define each(itr,c) for(__typeof(c.begin()) itr=c.begin(); itr!=c.end(); ++itr)
#define all(x) (x).begin(),(x).end()
#define mp make_pair
#define pb push_back
#define fi first
#define se second
const ll mod=1e9+7;
ll mod_fact(ll x)
{
    ll ret=1;
    for(ll i=2; i<=x; ++i) (ret*=i)%=mod;
    return ret;
}
//x^n
ll mod_pow(ll x, ll n)
{
    ll ret=1;
    ll pw[40];
    pw[0]=x;
    for(int i=1; i<40; ++i) pw[i]=(pw[i-1]*pw[i-1])%mod;
    rep(i,40)
    {
        if(n>>i&1) (ret*=pw[i])%=mod;
    }
    return ret;
}
ll mod_inv(ll x)
{
    ll pw[32];
    pw[0]=x;
    for(int i=1; i<32; ++i) pw[i]=(pw[i-1]*pw[i-1])%mod;
    ll p=mod-2;
    ll ret=1;
    rep(i,32)
    {
        if(p>>i&1) (ret*=pw[i])%=mod;
    }
    return ret;
}
int main()
{
    ll n,m;
    cin >>n >>m;
    ll ans=0;
    if(n>=m)
    {
        int sgn=1;
        ll a=mod_fact(m);
        ll b=a;
        ll c=1;
        for(ll i=m; i>=1; --i)
        {
            ll mul=1;
            //mCi
            (mul*=a)%=mod;
            (mul*=mod_inv(b))%=mod;
            (mul*=mod_inv(c))%=mod;
            //printf("b= %lld c= %lld\n", b,c);
            (b*=mod_inv(i))%=mod;
            (c*=(m-i+1))%=mod;
            //i^n
            (mul*=mod_pow(i,n))%=mod;
            ans=(ans+sgn*mul+mod)%mod;
            sgn=-sgn;
        }
    }
    cout << ans << endl;
    return 0;
}
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX