快速读入-读入外挂

 1 void read(int &x)
 2 {
 3     int f = 1;    x = 0;
 4     char ch = getchar ();
 5     while ((ch < ‘0‘ || ch > ‘9‘) && ch != ‘-‘)
 6         ch = getchar ();
 7     if (ch == ‘-‘)
 8     {
 9         f = -1;        ch = getchar ();
10     }
11     while (ch >= ‘0‘ && ch <= ‘9‘)
12     {
13         x = x * 10 + ch - ‘0‘;
14         ch = getchar ();
15     }
16
17     x *= f;
18 }