头文件模板【暂用

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#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<iomanip>
#include<bitset>
#include<queue>
#define LL long long
#define get(a,i) a&(1<<(i-1))
#define PAU putchar(' ')
#define ENT putchar('\n')
#define clr(a,b) memset(a,b,sizeof(a))
#define fo(_i,_a,_b) for (int _i=_a;_i<=_b;_i++)
#define down(_i,_a,_b) for (int _i=_a;_i>=_b;_i--)
#define efo(_i,_a) for (int _i=last[_a];_i!=0;_i=e[_i].next)
#define file(x) freopen(#x".in","r",stdin),freopen(#x".out","w",stdout);
#define end system("pause")
using namespace std;
LL read()
{
LL f=1,d=0;char s=getchar();
while (s<'0'||s>'9'){if (s=='-') f=-1;s=getchar();}
while (s>='0'&&s<='9'){d=d*10+s-'0';s=getchar();}
return f*d;
}
LL readln()
{
LL f=1,d=0;char s=getchar();
while (s<'0'||s>'9'){if (s=='-') f=-1;s=getchar();}
while (s>='0'&&s<='9'){d=d*10+s-'0';s=getchar();}
while (s!='\n') s=getchar();
return f*d;
}
inline void write(LL x)
{
if(x==0){putchar('0');return;}if(x<0)putchar('-'),x=-x;
int len=0,buf[20];while(x)buf[len++]=x%10,x/=10;
for(int i=len-1;i>=0;i--)putchar(buf[i]+'0');return;
}
inline void writeln(LL x){write(x);ENT;}