1. //读数字
    2. inline int read() {
    3.     char c = getchar();
    4.     int x = 0, f = 1;
    5.     while (c<'0' || c>'9') {
    6.         if(c == '-')
    7.             f = -1;
    8.         c = getchar();
    9.     }
    10.     while (c>='0' && c<='9') {
    11.         x = x*10+c-'0';
    12.         c = getchar();
    13.     }
    14.     return x * f;
    15. }
    17. //读单个字符（不要用scanf("%c", &ch)）
    18. char readc() {
    19.     char c = getchar();
    20.     while (c!='R' && c!='F')
    21.         c = getchar();
    22.     return c;
    23. }
    25. //关闭同步流
    26. ios::sync_with_stdio(false);
    27. cin.tie(0)