Submission #23601

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Source Code Expand

#include <cstdio>
#include <iostream>
#include <sstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <climits>
#include <cfloat>
using namespace std;

void integerFactorization(int n, vector<int>& base, vector<int>& expo)
{
    base.clear();
    expo.clear();
    int a = 2;
    while(a * a <= n){
        int b = 0;
        while(n % a == 0){
            ++ b;
            n /= a;
        }
        if(b > 0){
            base.push_back(a);
            expo.push_back(b);
        }
        ++ a;
    }
    if(n > 1 || base.size() == 0){
        base.push_back(n);
        expo.push_back(1);
    }
}

class Mod
{
    static const int MOD = 1000000007;
    long long a;
public:
    Mod(){
        a = 0;
    }
    Mod(long long x){
        a = (x % MOD + MOD) % MOD;
    }
    const Mod operator+(const Mod& x) const{
        return Mod(a + x.a);
    }
    const Mod operator-(const Mod& x) const{
        return Mod(a - x.a);
    }
    const Mod operator*(const Mod& x) const{
        return Mod(a * x.a);
    }
    const Mod operator/(const Mod& x) const{ // フェルマーの小定理、x.aがMODと互いに素な場合のみ有効
        int b = MOD - 2;
        long long c = x.a;
        long long ret = 1;
        while(b > 0){
            if(b & 1){
                ret *= c;
                ret %= MOD;
            }
            c *= c;
            c %= MOD;
            b >>= 1;
        }
        return Mod(a * ret);
    }
    long long getValue(){
        return a;
    }
};

Mod combination(int n, int r) // 組合せ
{
    Mod ret(1);
    for(int i=0; i<r; i++){
        ret = ret * n;
        n = n - 1;
        ret = ret / (i+1);
    }
    return ret;
}

Mod homogeneous(int n, int r) // 重複組合せ
{
    return combination(n+r-1,r);
}

int main()
{
    int n, m;
    cin >> n >> m;

    bool minus = false;
    if(n < 0){
        minus = true;
        n *= -1;
    }

    vector<int> base, expo;
    integerFactorization(n, base, expo);

    Mod ret(1);
    for(unsigned i=0; i<expo.size(); ++i){
        if(base[i] != 1)
            ret = ret * homogeneous(m, expo[i]);
    }

    Mod x(1);
    for(int i=0; i<m-1; ++i)
        x = x * 2;

    ret = ret * x;

    cout << ret.getValue() << endl;

    return 0;
}

Submission Info

Judge Result