zoukankan      html  css  js  c++  java
  • lightoj1197区间素数筛

    模板题,不过好像有点问题,当a==1的时候,答案把一也算进去了,要减去

    #include<map>
    #include<set>
    #include<cmath>
    #include<queue>
    #include<stack>
    #include<vector>
    #include<cstdio>
    #include<cassert>
    #include<iomanip>
    #include<cstdlib>
    #include<cstring>
    #include<iostream>
    #include<algorithm>
    #define pi acos(-1.0)
    #define ll long long
    #define mod 1000000007
    #define ls l,m,rt<<1
    #define rs m+1,r,rt<<1|1
    #pragma comment(linker, "/STACK:1024000000,1024000000")
    
    using namespace std;
    
    const double g=10.0,eps=1e-7;
    const int N=100000+10,maxn=500+100,inf=0x3f3f3f;
    
    bool prime[N],primesmall[N];
    ll seg_prime(ll a,ll b)
    {
        memset(prime,0,sizeof prime);
        for(ll i=0;i*i<b;i++)primesmall[i]=1;
        for(ll i=0;i<=b-a;i++)prime[i]=1;
        for(ll i=2;i*i<b;i++)
        {
            if(primesmall[i])
            {
                for(ll j=2*i;j*j<b;j+=i)primesmall[j]=0;
                for(ll j=max((ll)2,(a+i-1)/i)*i;j<=b;j+=i)prime[j-a]=0;
            }
        }
        ll ans=0;
        for(ll i=0;i<=b-a;i++)
            if(prime[i])
               ans++;
        return ans;
    }
    int main()
    {
        ios::sync_with_stdio(false);
        cin.tie(0);
        ll t,cnt=0;
        cin>>t;
        while(t--){
            ll a,b;
            cin>>a>>b;
            if(a==1)cout<<"Case "<<++cnt<<": "<<seg_prime(a,b)-1<<endl;
            else cout<<"Case "<<++cnt<<": "<<seg_prime(a,b)<<endl;
        }
        return 0;
    }
    /*********************
    9
    2 36
    3 73
    3 11
    1 1
    1 2
    2147383647 2147483647
    23990500 24000500
    24000501 24100501
    23999500 24010501
    *********************/
    View Code
  • 相关阅读:
    Hadoop 文件系统命令行基础
    Mac bash 远程连接阿里云服务器
    Master in Vocab -- Day Six
    Master in Vocab -- Day Five
    Master in Vocab -- Day Four
    Master in Vocab -- Day Three
    mybatis学习一
    mysql事务,视图,权限管理,索引,存储引擎(胖胖老师)
    SpringAOP
    Spring事务
  • 原文地址:https://www.cnblogs.com/acjiumeng/p/7227604.html
Copyright © 2011-2022 走看看