VJ数论专题AC代码临时保存

//A
#include<bits/stdc++.h>

using namespace std;

bool vis[1000010];

void Get_Prime()
{
    int n = 1000010;
    int m = sqrt(n+0.5);
    memset(vis,0,sizeof(vis));
    for(int i=2; i<=m; i++) if(!vis[i])
        for(int j=i*i; j<=n; j+=i) vis[j] = 1;
    return ;
}

int Find(int n)
{
    for(int i=n+1; ; i++)
       if(!vis[i]) return i;
}

int main()
{
    Get_Prime();
    int t,n,x;
    long long sum;
    scanf("%d",&t);
    for(int i=1; i<=t; i++)
    {
        scanf("%d",&n);
        sum = 0;
        while(n--)
        {
            scanf("%d",&x);
            sum += Find(x);
        }
        printf("Case %d: %lld Xukha\n",i,sum);
    }
    return 0;
}

//C
#include<bits/stdc++.h>
#define MAXN 1000010

using namespace std;

bool vis[MAXN+10];
long int prime[MAXN+10];
long cnt,cnt1,cnt2;

void GetPrime()
{
    cnt = 0;
    memset(vis,0,sizeof(vis));
    for(long int i=2; i<MAXN; i++)
    {
        if(!vis[i]) prime[cnt++] = i;
        for(int j=0; j<cnt && i * prime[j] < MAXN; j++)
        {
            vis[i * prime[j]] = 1;
            if(!i%prime[j]) break;
        }
    }
    return ;
}

long long int GetY(long int n)
{
    cnt1 = 0;
    long long sum = 1;
    long m = sqrt(n);
    while(n>1 && prime[cnt1] <= m)
    {
        long cc=0;
        while(n%prime[cnt1] == 0 && n > 1)
        {
            cc++;
            n/=prime[cnt1];
        }
        sum *= cc + 1;
        cnt1++;
    }
    if(n!=1) sum *= 2;
    return sum;
}

int main()
{
    GetPrime();
    int t;
    long a,b;
    scanf("%d",&t);
    for(int j=1; j<=t; j++)
    {
        scanf("%ld %ld",&a,&b);
        if(b * b >= a)
        {
            printf("Case %d: 0\n",j);
            continue;
        }
        long long ans = GetY(a);
        ans /= 2;
        for(int i = 1; i<b; i++)
            if(a%i == 0) ans--;
        printf("Case %d: %lld\n",j,ans);
    }
    return 0;
}

//D
#include<bits/stdc++.h>

using namespace std;

int main()
{
    int t,cnt=0;
    long long n,k;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%lld",&n);
        k = n;
        n -= (long long)sqrt(k);
        n -= (long long)sqrt(k/2);
        printf("Case %d: %lld\n",++cnt,n);
    }
    return 0;
}

#include<cstdio>
#include<cstdlib>
#include<cstring>

using namespace std;

const int MAXN = 3e5 + 10;
char s[50010][50];
int tree[MAXN][26];
bool flagg[MAXN];
int cnt;

void Insert(char *str)
{
    int len = strlen(str);
    int root = 0;
    for(int i=0; i<len; i++)
    {
        int id = str[i] - 'a';
        if(!tree[root][id]) tree[root][id] = ++cnt;
        root = tree[root][id];
    }
    flagg[root] = true;
    return ;
}

int Find(char *str, int n)
{
    int len = strlen(str);
    int root = 0;
    int x = 0;
    for(int i=0; i<len; i++)
    {
        int id = str[i] - 'a';
        root = tree[root][id];
        if(n!=-1 && flagg[root]==true && i<len-1)
        {
            if((x++) == n)
                return i;
        }
    }
    if(n==-1 && flagg[root] == true) return 1;
    return -1;
}

int main()
{
    char s1[25],s2[25];
    memset(tree,0,sizeof(tree));
    memset(flagg,0,sizeof(flagg));
    int j = cnt = 0;
    while(~scanf("%s",s[j]))
    {
        Insert(s[j++]);
    }
    for(int i=0; i<j; i++)
    {
        bool flag = false;
        for(int l=0; ;l++)//L表示要查找单词的第几个前缀
        {
            int d = Find(s[i],l);
            if(d == -1) break;//如果已经找不到前缀表示该单词不可能是两部分拼成的
            d = Find(&s[i][d+1],-1);//-1表示要查找的是单词的后缀部分
            if(d==1)//如果能找到相应后缀表示该单词是拼接而成
            {
                flag = true;
                break;
            }
        }
        if(flag) printf("%s\n",s[i]);
    }
    return 0;
}