zoukankan      html  css  js  c++  java
  • E

    Today XianYu is too busy with his homework, but the boring GuGu is still disturbing him!!!!!! 
    At the break time, an evil idea arises in XianYu's mind. 
    ‘Come on, you xxxxxxx little guy.’ 
    ‘I will give you a function ϕ(x)ϕ(x) which counts the positive integers up to xx that are relatively prime to xx.’ 
    ‘And now I give you a fishtion, which named GuGu Fishtion, in memory of a great guy named XianYu and a disturbing and pitiful guy GuGu who will be cooked without solving my problem in 5 hours.’ 
    ‘The given fishtion is defined as follow: 
    Gu(a,b)=ϕ(ab)ϕ(a)ϕ(b)Gu(a,b)=ϕ(ab)ϕ(a)ϕ(b)

    And now you, the xxxxxxx little guy, have to solve the problem below given mm,nn,pp.’ 
    (a=1mb=1nGu(a,b))(modp)(∑a=1m∑b=1nGu(a,b))(modp)

    So SMART and KINDHEARTED you are, so could you please help GuGu to solve this problem? 
    ‘GU GU!’ GuGu thanks. 

    InputInput contains an integer TT indicating the number of cases, followed by TT lines. Each line contains three integers mm,nn,pp as described above. 
    1T31≤T≤3 
    1m,n1,000,0001≤m,n≤1,000,000 
    max(m,n)<p1,000,000,007max(m,n)<p≤1,000,000,007 
    And given pp is a prime. 
    OutputPlease output exactly TT lines and each line contains only one integer representing the answer. 
    Sample Input

    1
    5 7 23

    Sample Output

    2

    Solution:

    phi(ab) = phi(a)*phi(b)*gcd(a,b)/phi(gcd(a,b))
    然后在去枚举gcd就行了
    递推逆元爆int?

    Code:
    #include<bits/stdc++.h>
    using namespace std;
    const int maxn = 1e6+100;
    typedef long long ll;
    int fac[maxn],mu[maxn],phi[maxn];
    int g[maxn];
    ll inv[maxn];
    void init()
    {
        for(int i=1; i<maxn; ++i)
            fac[i]=i;
        phi[1]=mu[1]=1;
        for(int i=2; i<maxn; ++i)
        {
            if(fac[i]==i)
                for(int j=i<<1; j<maxn; j+=i)
                    fac[j]=i;
            if(i/fac[i]%fac[i])
                phi[i]=(fac[i]-1)*phi[i/fac[i]],mu[i]=-mu[i/fac[i]];
            else
                phi[i]=fac[i]*phi[i/fac[i]],mu[i]=0;
        }
    }
    int n,m,p;
    
    signed main()
    {
        ios::sync_with_stdio(0);
        init();
        int T;
        cin>>T;
        while(T--)
        {
            cin>>n>>m>>p;
            int M=min(n,m);
    
            for(int i=1; i<=M; i++)
            {
                g[i]=0;
                int MM=min(n/i,m/i);
                int A=n/i;
                int B=m/i;
                for(int d=1; d<=MM; d++)
                    g[i] += 1ll*mu[d]*(n/i/d)*(m/i/d)%p,g[i]%=p;
                if(g[i]<0)
                    g[i] += p;
            }
    
            int ans=0;
            inv[1]=1;
            for( int i=2; i<=M; i++)
            {
                inv[i]=1ll*(p-p/i)*inv[p%i]%p;
            }
            for(int k=1; k<=M; k++)
            {
                ans=(1ll*ans+1ll*k*inv[phi[k]]%p*1ll*g[k]%p)%p;
            }
            cout<<ans<<endl;
    
    
        }
    // 5 1000000 1000000 1000000007
    }
    

      







  • 相关阅读:
    Android 数据库
    HarmonyOS三方件开发指南(12)——cropper图片裁剪
    从微信小程序到鸿蒙js开发【15】——JS调用Java
    鸿蒙的js开发部模式16:鸿蒙布局Grid网格布局的应用一
    从微信小程序到鸿蒙js开发【14】——自定义组件
    鸿蒙js开发7 鸿蒙分组列表和弹出menu菜单
    HarmonyOS三方件开发指南(11)——Updownfile
    鸿蒙Java开发模式11:鸿蒙图片裁剪功能的实现
    从微信小程序到鸿蒙js开发【13】——list加载更多&回到顶部
    从微信小程序到鸿蒙js开发【12】——storage缓存&自动登录
  • 原文地址:https://www.cnblogs.com/zhangbuang/p/11881187.html
Copyright © 2011-2022 走看看