fread优化读入
inline char nc()
{
static const int BS = 1 << 22;
static unsigned char buf[BS],*st,*ed;
if(st == ed) ed = buf + fread(st=buf,1,BS,stdin);
return st == ed ? EOF : *st++;
}
//#define nc getchar
inline int read()
{
char ch;
int res = 0; bool flag = 0;
while (!isdigit(ch = nc()));
while (ch >= '0' and ch <= '9')
{
res = (res << 1) + (res << 3) + (ch - '0');
ch = nc();
}
return res;
}
卡常