代码

void my_memset(char *a, char c, unsigned n) {
    unsigned nn = n / 8;
    long long *aa = (long long*) a;
    long long cc = c;
    cc = cc << 8 | cc;
    cc = cc << 16 | cc;
    cc = cc << 32 | cc;
    unsigned nnn = nn & ~7;
    for(unsigned i = 0; i < nnn; i += 8) {
        aa[i] = cc;
        aa[i + 1] = cc;
        aa[i + 2] = cc;
        aa[i + 3] = cc;
        aa[i + 4] = cc;
        aa[i + 5] = cc;
        aa[i + 6] = cc;
        aa[i + 7] = cc;
    }
    nnn *= 8;
    for (unsigned i = nnn; i < n; i ++) {
        a[i] = c;
    }
}

评测结果