杂项

快读

template<typename T>void in(T &a)
{
  T ans=0;
  bool f=0;
  char c=getchar();
  for(;c<'0'||c>'9';c=getchar())if(c=='-')f=1;
  for(;c>='0'&&c<='9';c=getchar())ans=ans*10+c-'0';
  a=f?-ans:ans;
}
template<typename T,typename... Args>void in(T &a,Args&...args)
{
  in(a),in(args...);
}

非负数快读

template<typename T>void in(T &a)
{
  T ans=0;
  char c=getchar();
  for(;c<'0'||c>'9';c=getchar());
  for(;c>='0'&&c<='9';c=getchar())ans=ans*10+c-'0';
  a=ans;
}
template<typename T,typename... Args>void in(T &a,Args&...args)
{
  in(a),in(args...);
}

fread快读

char buf1[2097152],*ip1=buf1,*ip2=buf1;
inline int getc(){
  return ip1==ip2&&(ip2=(ip1=buf1)+fread(buf1,1,2097152,stdin),ip1==ip2)?EOF:*ip1++;
}
template<typename T>void in(T &a)
{
  T ans=0;
  bool f=0;
  char c=getc();
  for(;c<'0'||c>'9';c=getc())if(c=='-')f=1;
  for(;c>='0'&&c<='9';c=getc())ans=ans*10+c-'0';
  a=(f?-ans:ans);
}
template<typename T,typename... Args>void in(T &a,Args&...args)
{
  in(a),in(args...);
}

非负数fread快读

char buf1[2097152],*ip1=buf1,*ip2=buf1;
inline int getc(){
  return ip1==ip2&&(ip2=(ip1=buf1)+fread(buf1,1,2097152,stdin),ip1==ip2)?EOF:*ip1++;
}
template<typename T>void in(T &a)
{
  T ans=0;
  char c=getc();
  for(;c<'0'||c>'9';c=getc());
  for(;c>='0'&&c<='9';c=getc())ans=ans*10+c-'0';
  a=ans;
}
template<typename T,typename... Args>void in(T &a,Args&...args)
{
  in(a),in(args...);
}

快写

template<typename T>void __out(T x)
{
  (x>9)&&(__out(x/10),0),putchar(x%10+48);
}
template<typename T>void out(T x)
{
  if(x<0)x=-x,putchar('-');
  __out(x);
}

加速 cin 和 cout

ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);

手动吸氧

#pragma GCC optimize("Ofast,unroll-loops")

离散化

void rebuild(int n,int a[],int cnt=0){
  int temp[n+5];
  for(int i=1;i<=n;i++)temp[i]=a[i];
  sort(temp+1,temp+n+1),cnt=unique(temp+1,temp+n+1)-temp-1;
  for(int i=1;i<=n;i++)a[i]=lower_bound(temp+1,temp+cnt+1,a[i])-temp;
}

__gnu_pbds

//哈希表
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
__gnu_pbds::gp_hash_table<int,int>a;
//优先队列
#include<ext/pb_ds/priority_queue.hpp>
__gnu_pbds::priority_queue<int,greater<int>,__gnu_pbds::pairing_heap_tag>a;//配对堆 
__gnu_pbds::priority_queue<int,greater<int>,__gnu_pbds::thin_heap_tag>b;//冗余计数二项堆
__gnu_pbds::priority_queue<int,greater<int>,__gnu_pbds::binomial_heap_tag>c;//二项堆 
__gnu_pbds::priority_queue<int,greater<int>,__gnu_pbds::rc_binomial_heap_tag>d;//斐波那契堆 
__gnu_pbds::priority_queue<int,greater<int>,__gnu_pbds::binary_heap_tag>e;//二叉堆 
__gnu_pbds::priority_queue<int,greater<int>,__gnu_pbds::TAG>::point_iterator it;//迭代器 

DLX

int head[n+5],sz[m+5],l[k+5],r[k+5],u[k+5],d[k+5],cnt,x[k+5],y[k+5],num,ans[n+5];
void build(int b){
  cnt=b;
  for(int i=0;i<=b;i++)l[i]=i?i-1:b,r[i]=i==b?0:i+1,u[i]=d[i]=i;
}
void insert(int a,int b){
  sz[b]++,cnt++,x[cnt]=a,y[cnt]=b,u[cnt]=b,d[cnt]=d[b],u[d[cnt]]=d[u[cnt]]=cnt;
  if(!head[a])head[a]=l[cnt]=r[cnt]=cnt;
  else l[cnt]=head[a],r[cnt]=r[head[a]],l[r[cnt]]=r[l[cnt]]=cnt;
}
void remove(int a){
  l[r[a]]=l[a],r[l[a]]=r[a];
  for(int i=d[a];i!=a;i=d[i])for(int j=r[i];j!=i;j=r[j])u[d[j]]=u[j],d[u[j]]=d[j],sz[y[j]]--;
}
void recover(int a){
  for(int i=u[a];i!=a;i=u[i])for(int j=l[i];j!=i;j=l[j])u[d[j]]=d[u[j]]=j,sz[y[j]]++;
  l[r[a]]=a,r[l[a]]=a;
}
bool dance(){
  int pos=r[0];
  if(!pos)return 1;
  for(int i=r[0];i;i=r[i])if(sz[i]<sz[pos])pos=i;
  remove(pos),num++;
  for(int i=d[pos];i!=pos;i=d[i]){
    ans[num]=x[i];
    for(int j=r[i];j!=i;j=r[j])remove(y[j]);
    if(dance())return 1;
    for(int j=l[i];j!=i;j=l[j])recover(y[j]);
  }
  return recover(pos),num--,0;
}