代码

typedef unsigned long long u64;
struct DI { u64 abi; const char*in; u64 insz; char*out; u64 outlim; u64 outsz; char*err;
            u64 errlim; u64 errsz; const char*IB; u64 IBlim; char*OB; u64 OBlim; u64 tscfreq; }
            __attribute__((packed));
static inline void rx(){
    register long rax __asm__("rax")=60;
    register long rdi __asm__("rdi")=0;
    __asm__ volatile("syscall" :: "a"(rax),"D"(rdi) : "rcx","r11","memory");
    __builtin_unreachable();
}
extern "C" int __libc_start_main(int (*m)(int,char**,char**), int argc, char **v,
                                 void (*i)(void), void (*f)(void), void (*l)(void)) {
    char **env = v + argc + 1;
    while (*env) env++;
    u64 *a = (u64*)(env+1);
    DI *di = 0;
    for (; a[0]; a += 2) if (a[0] == 0x6b637564ULL) { di = (DI*)a[1]; break; }
    const char *p = di->IB_ptr;
    u64 x=0,y=0;
    while (*p >= '0') x = x*10 + (u64)(*p++ - '0');
    while (*p < '0' || *p > '9') p++;
    while (*p >= '0') y = y*10 + (u64)(*p++ - '0');
    u64 val = x*y - x - y;
    char buf[24]; int k=0;
    if (!val) buf[k++]='0';
    while (val) { buf[k++] = (char)('0' + val%10); val/=10; }
    char *o = di->out;
    while (k) *o++ = buf[--k];
    *o++ = '\n';
    di->outsz = (u64)(o - di->out);
    rx();
    return 0;
}

评测结果