例如这个快读

inline int read(){
   int x=0,f=1;
   char ch=getchar();
   while(ch<'0'||ch>'9')
   {
   	if(ch=='-')
     	f=-1;
  	 ch=getchar();
   }
   while(ch>='0'&&ch<='9') 
   {
  	 x=(x<<1)+(x<<3)+ch-'0';
  	 ch=getchar();
   }
   return x*f;
}