代码

typedef unsigned long U;

static char **initial_argv;
static U initial_argc;

U getauxval(U key) {
    char **p = initial_argv + initial_argc + 1;
    while (*p) ++p;
    U *aux = (U *)(p + 1);
    while (aux[0]) {
        if (aux[0] == key) return aux[1];
        aux += 2;
    }
    return 0;
}

int binary_search(const unsigned *a, int n, unsigned x) {
    unsigned lo = 0, hi = (unsigned)n - 1;
    while (lo < hi) {
        unsigned mid = lo + ((hi - lo + 1) >> 1);
        if (a[mid] <= x)
            lo = mid;
        else
            hi = mid - 1;
    }
    return (int)lo;
}

__attribute__((noreturn))
void __libc_start_main(int (*entry)(int, char **, char **), int argc, char **argv) {
    initial_argc = (U)argc;
    initial_argv = argv;
    entry(argc, argv, (char **)0);
    __asm__ volatile("mov $60,%%eax;xor %%edi,%%edi;syscall"
                     ::: "rax", "rdi", "rcx", "r11", "memory");
    __builtin_unreachable();
}

评测结果