fastIO

不考虑内存浪费的fastIO

#include<bits/stdc++.h>
using namespace std;
namespace IO
{
    const int len=1<<25;
    bool flag;
    char ch,ibuf[len],wbuf[len];
    int il=0,wl=0,g,G[55];
    void in(){int x=fread(ibuf,1,len,stdin);}
    inline void out(){int x=fwrite(wbuf,1,wl,stdout);}
    inline void gc(char&c){c=ibuf[il++];}
    template<typename T>void read(T&x)
    {
        flag=0;gc(ch);
        if(ch=='-')flag=1;
        while(!isdigit(ch)){if(ch=='-')flag=1;gc(ch);}
        x=ch-'0';gc(ch);
        while(isdigit(ch)){x=x*10+ch-'0';gc(ch);}
        x=flag?-x:x;
    }
    template<typename T>void write(T x)
    {
        if(x<0)wbuf[wl++]='-',x=-x;
        g=0;
        do{G[++g]=x%10;x/=10;}while(x);
        for(int i=g;i>=1;--i)wbuf[wl++]='0'+G[i];
        wbuf[wl++]='
';
    }
}
int main()
{
    ios::sync_with_stdio(false);
    IO::in();
    IO::out();
    return 0;
}

若总共需要读入和输出len个字符，需占用len/1048576*2 Mb的内存。