真的读入优化与假的读入优化

一直以来，我都是这样写读入优化的。

inline char nc() {
    static char b[100000],*s=b,*t=b;
    return s==t&&(t=(s=b)+fread(b,1,100000,stdin),s==t)?-1:*s++;
}
inline void read(int &x) {
    static char buf = nc(); x = 0; static int op = 1;
    for (; !isdigit(buf); buf = nc()) if (buf == '-') op = -1;
    for (; isdigit(buf); buf = nc()) x = x * 10 + buf - '0'; x *= op;
}

然后有道题死活过不去，把读入优化改成scanf就过了。这才发现，我一直都写的是假的！！！！读入优化！！！！

真正的读入优化要这样写！！

inline char nc() {
    static char b[100000],*s=b,*t=b;
    return s==t&&(t=(s=b)+fread(b,1,100000,stdin),s==t)?-1:*s++;
}
inline void read(int &x) {
    static char buf = nc(); x = 0; int op = 1;
    for (; !isdigit(buf); buf = nc()) if (buf == '-') op = -1;
    for (; isdigit(buf); buf = nc()) x = x * 10 + buf - '0'; x *= op;
}

　又测了测速，貌似不写static更快？

inline char nc() {
    static char b[100000],*s=b,*t=b;
    return s==t&&(t=(s=b)+fread(b,1,100000,stdin),s==t)?-1:*s++;
}
inline void read(int &x) {
    char buf = nc(); x = 0; int op = 1;
    for (; !isdigit(buf); buf = nc()) if (buf == '-') op = -1;
    for (; isdigit(buf); buf = nc()) x = x * 10 + buf - '0'; x *= op;
}

　震惊！把int换成short又可以变快！

inline char nc() {
    static char b[100000],*s=b,*t=b;
    return s==t&&(t=(s=b)+fread(b,1,100000,stdin),s==t)?-1:*s++;
}
inline void read(int &x) {
    char buf = nc(); x = 0; short op = 1;
    for (; !isdigit(buf); buf = nc()) if (buf == '-') op = -1;
    for (; isdigit(buf); buf = nc()) x = x * 10 + buf - '0'; x *= op;
}