scanf变成fread的读入优化
```cpp
inline char nc()
{
static char buf[100000],*p1=buf,*p2=buf;
return p1==p2&&(p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++;
}
inline int read()
{
int X=0,w=0; char ch=0;
while(!isdigit(ch)) {w|=ch=='-';ch=nc();}
while(isdigit(ch)) X=X*10+(ch^48),ch=nc();
return w?-X:X;
}
```
by chen_zhe @ 2018-02-11 13:45:41