算是回归的第一晚 (啥也不记得了。。从模板开刷！！)

#include <ctype.h>
#include <cstdio>
#define N 10000050

void read(int &x)
{
    x=0;bool f=0;
    char ch=getchar();
    while(!isdigit(ch)) {if(ch==‘-‘) f=1;ch=getchar();}
    while(isdigit(ch)) {x=x*10+(int)ch-‘0‘;ch=getchar();}
    x=f?(~x)+1:x;
}
int n,m,Prime[N],num;
bool isPrime[N];
int main()
{
    read(n);read(m);
    for(int i=2;i<=n;i++)
    {
        if(!isPrime[i]) Prime[num++]=i;
        for(int j=0;j<num&&i*Prime[j]<=n;j++)
        {
            isPrime[i*Prime[j]]=1;
            if(i%Prime[j]==0) break;
        }
    }
    isPrime[0]=isPrime[1]=1;
    for(int x;m--;)
    {
        read(x);
        if(isPrime[x]) printf("No\n");
        else printf("Yes\n");
    }
    return 0;
}

【模板】线性筛素数

#include <ctype.h>
#include <cstdio>
#define N 10050

void read(int &x)
{
    x=0;bool f=0;
    char ch=getchar();
    while(!isdigit(ch)) {if(ch==‘-‘) f=1;ch=getchar();}
    while(isdigit(ch)) {x=x*10+(int)ch-‘0‘;ch=getchar();}
    x=f?(~x)+1:x;
}
int fa[N],n,m;
int find_(int x){return fa[x]==x?x:fa[x]=find_(fa[x]);}
int main()
{
    read(n);read(m);
    for(int i=1;i<=n;i++) fa[i]=i;
    for(int type,x,y;m--;)
    {
        read(type);read(x);read(y);
        if(type==1)
        {
            int fx=find_(x),fy=find_(y);
            if(fx!=fy) fa[fy]=fx;
        }
        else if(type==2) find_(x)==find_(y)?printf("Y\n"):printf("N\n");
    }
    return 0;
}

【模板】并查集

#include <ctype.h>
#include <cstdio>
#define N 4000005

void read(int &x)
{
    x=0;bool f=0;char ch=getchar();
    while(!isdigit(ch)) {if(ch==‘-‘) f=1;ch=getchar();}
    while(isdigit(ch)) {x=x*10+(int)ch-‘0‘;ch=getchar();}
    x=f?(~x)+1:x;
}
int n,heap[N],top;
void swap(int &x,int &y)
{
    int tmp=y;
    y=x;
    x=tmp;
}
void push_heap(int m)
{
    heap[++top]=m;
    int now=top;
    while(now>1)
    {
        int next=now/2;
        if(heap[next]<heap[now]) break;
        swap(heap[now],heap[now/2]);
        now=next;
    }
}
void heap_pop()
{
    heap[1]=heap[top--];
    int now=1;
    while(now*2<=top)
    {
        int next=now<<1;
        if(heap[next]>heap[next+1]) next++;
        if(heap[next]>=heap[now]) break;
        swap(heap[next],heap[now]);
        now=next;
    }
}
int main()
{
    read(n);
    for(int x,y;n--;)
    {
        read(x);
        if(x==1) read(y),push_heap(y);
        else if(x==2) printf("%d\n",heap[1]);
        else heap_pop();
    }
    return 0;
}

【模板】堆

#include <algorithm>
#include <ctype.h>
#include <cstdio>
#define N 200005
using namespace std;
void read(int &x)
{
    x=0;bool f=0;
    char ch=getchar();
    while(!isdigit(ch)) {if(ch==‘-‘) f=1;ch=getchar();}
    while(isdigit(ch)) {x=x*10+(int)ch-‘0‘;ch=getchar();}
    x=f?(~x)+1:x;
}
int n,m;
struct node
{
    int x,y,z;
    bool operator<(node a)const
    {
        return z<a.z;
    }
}edge[N];
bool vis[N];
int fa[N],cnt;
int find_(int x)
{
    return x==fa[x]?x:fa[x]=find_(fa[x]);
}
int main()
{
    read(n);read(m);
    for(int i=1;i<=n;i++) fa[i]=i;
    for(int x,y,z;m--;)
    {
        read(x);read(y);read(z);
        edge[++cnt].x=x;
        edge[cnt].y=y;
        edge[cnt].z=z;
    }
    sort(edge+1,edge+1+cnt);
    int ans=0,num=0;
    for(int i=1;i<=cnt;i++)
    {
        int fx=edge[i].x,fy=edge[i].y;
        if(find_(fx)!=find_(fy))
        {
            fa[find_(fy)]=find_(fx);
            ans+=edge[i].z;
            num++;
            if(num==n-1) break;
         }
    }
    printf("%d\n",ans);
    return 0;
}

【模板】最小生成树