11.3 上午考试

 

 

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<cmath>
using namespace std;
int l,tot,topt;
int f[1<<24];
int ans[200010];
char s[20000010];
int main()
{
    freopen("ab.in","r",stdin);
    freopen("ab.out","w",stdout);
    scanf("%s",s+1);
    l=strlen(s+1);
    int r=ceil(log(l)/log(2)); 
    for(int i=1;i<=l;i++)
    {
        int x=0;
        for(int j=i;j<=i+r-1&&j<=l;j++)
        {
            x=x*2+s[j]-'A';
            f[x+(1<<j-i+1)]=1;
        }
    }
    int now,len=1,flag=0;
    while(1)
    {
        now=0;int ha=1<<len;
        while(now<=ha-1)
        {
            if(f[now+ha]==0)
            {
                ans[0]=len;flag=1;
                while(now)
                {
                    ans[len]=now%2;
                    now/=2;len--;
                }
                break;
            }
            now++;
        }
        len++;
        if(flag)break;
    }
    for(int i=1;i<=ans[0];i++)
      printf("%c",ans[i]+'A');
    printf("\n");
    return 0;
}

/*
60分暴力 
*/
#include<iostream>
#include<cstdio>
#include<cstring>
#define LL long long
using namespace std;
LL n,p,a,b,tot,ans;
LL prime[1000010];
int f[10000010];
LL init()
{
    LL x=0,f=1;char c=getchar();
    while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
    while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}
    return x*f;
}
void prepare(LL x)
{
    for(LL i=2;i<=x;i++)
    {
        if(!f[i])prime[++tot]=i;
        for(LL j=1;j<=tot&&prime[j]*i<=x;j++)
        {
            f[prime[j]*i]=1;
            if(i%prime[j]==0)break;
        }
    }
}
int main()
{
    freopen("prime.in","r",stdin);
    freopen("prime.out","w",stdout);
    p=init();a=init();b=init();
    prepare(p);
    for(int i=a;i<=b;i++)
      f[i-a+1]=i;
    for(int i=1;i<=tot;i++)
    {
        int l=a/prime[i]*prime[i];
        for(int j=l;j<=b;j+=prime[i])
        {
            if(j-a+1<=0)continue;
            while(f[j-a+1]%prime[i]==0)
              f[j-a+1]/=prime[i];
        }
    }
    for(int i=a;i<=b;i++)
      if(f[i-a+1]>1)ans++;
    cout<<ans<<endl;
    return 0;
}

 

/*
应该是正解
只要不爆栈(考试时老师设置了8M的栈)
*/
#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;
int n,p,a,b,tot,ans;
int prime[1000010];
int f[10000010];
int init()
{
    int x=0,f=1;char c=getchar();
    while(c<'0'||c>'9'){if(c=='-')f=-1;c=getchar();}
    while(c>='0'&&c<='9'){x=x*10+c-'0';c=getchar();}
    return x*f;
}
void prepare()
{
    for(int i=2;i<=p;i++)
    {
        if(!f[i])prime[++tot]=i;
        for(int j=1;j<=tot&&prime[j]*i<=p;j++)
        {
            f[prime[j]*i]=1;
            if(i%prime[j]==0)break;
        }
    }
}
int judge(int x,int mx)
{
    for(int i=2;i*i<=x;i++)
    {
        if(x%i==0)
        {
            if(i>mx)return 0;
            while(x%i==0)x/=i;
        }
    }
    if(x>mx)return 0;
    return 1;
}
int dfs(int l,int r,int x)
{
    if(l>r)return 0;
    if(x==0)return l==1;
    if(r<=prime[x])return r-l+1;
    if(l==r)return judge(l,prime[x]);
    return dfs(l,r,x-1)+dfs((l-1)/prime[x]+1,r/prime[x],x);
}
int main()
{
    freopen("prime.in","r",stdin);
    freopen("prime.out","w",stdout);
    p=init();a=init();b=init();
    prepare();
    cout<<b-a+1-dfs(a,b,tot)<<endl;
    return 0;
} 

 

 

暂无正解