一些常見的簡單最佳化

1：輸入最佳化

read

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

namespace io{
	const ll BUFSIZE=1<<20;
	char ibuf[BUFSIZE],*is=ibuf,*it=ibuf;
	char obuf[BUFSIZE],*os=obuf,*ot=obuf+BUFSIZE;
	inline char getch(){
		if(is==it)it=(is=ibuf)+fread(ibuf,1,BUFSIZE,stdin);
		return (is==it)?EOF:*is++;
	}
	inline ll read(){
		ll res=0;bool neg=false;char ch=getch();
		while(!(isdigit(ch)||ch=='-')&&ch!=EOF)ch=getch();
		if(ch=='-')neg=true,ch=getch();
		while(isdigit(ch))res=res*10+(ch-'0'),ch=getch();
		return neg?-res:res;
	}
	inline void flush(){
		fwrite(obuf,1,os-obuf,stdout);
		os=obuf;
	}
	inline void putch(char ch){
		*os++=ch;
		if(os==ot)flush();
	}
	inline void write(ll res){
		char q[25];ll top;
		if(res<0)putch('-'),res=-res;
		if(res==0)putch('0');			
		top=0;
		while(res)q[top++]=res%10+'0',res/=10;
		while(top--)putch(q[top]);
	}
}

2：O2最佳化

#pragma GCC optimize(1)
#pragma GCC optimize(2)
#pragma GCC optimize(3,"Ofast","inline")

暫時就更到這吧，以後有知道啥好用的再加