c++快读模版

inline int read() {
    int x = 0,f = 1;
    char ch = getchar();
    while (ch < '0' || ch>'9')
    {
        if (ch == '-')
            f = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9')
    {
        x = (x << 1) + (x << 3) + (ch ^ 48);
        ch = getchar();
    }
    return x * f;
}