Game with numbers

https://ac.nowcoder.com/acm/contest/942/B 

 

思路：处理出每个数的因子数，用s集合取剔除因子，因子都能去掉的就是合法的；

#include<algorithm>
#include<set>
#include<cmath>
#include<cstring>
#include<iostream>
#include<set>
#include<vector>
#include<queue>
#include<cmath>
#include<cstdio>
#include<map>
#include<stack>
#include<bits/stdc++.h>
using namespace std;

#define sfi(i) scanf("%d",&i)
#define sfs(i) scanf("%s",(i))
#define pri(i) printf("%d\n",i)
#define sff(i) scanf("%lf",&i)
#define ll long long
#define ull unsigned long long
#define mem(x,y) memset(x,y,sizeof(x))
#define INF 0x3f3f3f3f
#define eps 1e-16
#define PI acos(-1)
#define lowbit(x) ((x)&(-x))
#define zero(x) (((x)>0?(x):-(x))<eps)
#define fl() printf("flag\n")
#define MOD(x) ((x%mod)+mod)%mod
#define endl '\n'
#define pb push_back
#define lson rt<<1,l,mid
#define rson rt<<1|1,mid+1,r
#define FAST_IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)

const int maxn=3e5+9;
const int mod=1e9+7;

inline ll read()
{
    ll f=1,x=0;
    char ss=getchar();
    while(ss<'0'||ss>'9')
    {
        if(ss=='-')f=-1;ss=getchar();
    }
    while(ss>='0'&&ss<='9')
    {
        x=x*10+ss-'0';ss=getchar();
    }    return f*x;
}

ll power(ll x,ll n)
{
    ll ans=1;
    while(n)
    {
        if(n&1) ans=ans*x;
        x=x*x;
        n>>=1;
    }
    return ans;
}

int a[maxn];
int n,m;
int ans=0;
int vis[maxn];
int p[maxn];
int main()
{
    //FAST_IO;
    int t;
    cin>>t;
    mem(vis,0);
    for(int i=2;i<=maxn;i++)
    {
        for(int j=i+i;j<=maxn;j+=i) vis[j]++;
        if(!vis[i]) vis[i]=INF;
    }
    while(t--)
    {
        mem(p,INF);
        ans=0;
        cin>>n>>m;
        for(int i=0;i<=maxn;i++) p[i]=vis[i];
        for(int i=0;i<n;i++) cin>>a[i],p[a[i]]=0;

        for(int i=2;i<=m;i++)
        {
            if(p[i]<=0)
            {
                //cout<<i<<" ";
                for(int j=2*i;j<=m;j+=i) p[j]--;
                ans++;
            }

        }

        cout<<ans<<endl;
    }
    return 0;
}