非官方题解

进制转换怎么写我就不多讲了，网上一抓一大把 (主要因为作者比较懒)，这里我用的是 除n取余，倒序读取 的方法:

std::string q = "0123456789ABCDEF";
std::string ten_n (int n, int x)
{
    std::string s;
    while (x)
    {
        s = q[x % n] + s;
        x = x / n;
    }return s;
}

然后我们简简单单写个输入，再把所有的 8 进制数都算好，如下：

int n; std::cin >> n;
int a[N] {};
for (int i = 0; i < n; ++ i)
    std::cin >> a[i];
std::string b[N] {};
for (int i = 0; i < n; ++ i)
    b[i] = ten_n (8, a[i]);

再来个排序：

std::sort (b + 0, b + n, cmp);

这里的 cpm 函数比较难写，所以我们一步一步来。

题目中要求“先比最低位”，那我们就按照它说的写：

bool cmp (std::string x, std::string y)
{
    int len_x = (int) x.length ();
    int len_y = (int) y.length ();
    if (x[len_x - 1] != y[len_y - 1])
        return x[len_x - 1] > y[len_y - 1];
}

最低位相同，“直接从小到大比”：

bool cmp (std::string x, std::string y)
{
    int len_x = (int) x.length ();
    int len_y = (int) y.length ();
    if (x[len_x - 1] != y[len_y - 1])
        return x[len_x - 1] > y[len_y - 1];
    if (len_x != len_y)
        return len_x < len_y;
    return x < y;
}

这里注意，由于数据类型是 std::string，所以要自己写比较方法：先比位数，再比字典序。

最后再来个输出：

for (int i = 0; i < n; ++ i)
    std::cout << b[i] << ' ';

C++ Code:

#include <bits/stdc++.h>
#define Ll long long
//using namespace std;
const int N = 2e5 + 10, M = 1e2 + 10;

std::string q = "0123456789ABCDEF";
std::string ten_n (int n, int x)
{
    std::string s;
    while (x)
    {
        s = q[x % n] + s;
        x = x / n;
    }return s;
}bool cmp (std::string x, std::string y)
{
    int len_x = (int) x.length ();
    int len_y = (int) y.length ();
    if (x[len_x - 1] != y[len_y - 1])
        return x[len_x - 1] > y[len_y - 1];
    if (len_x != len_y)
        return len_x < len_y;
    return x < y;
}void solve ()
{
    //main;
    int n; std::cin >> n;
    int a[N] {};
    for (int i = 0; i < n; ++ i)
        std::cin >> a[i];
    std::string b[N] {};
    for (int i = 0; i < n; ++ i)
        b[i] = ten_n (8, a[i]);
    /*for (int i = 0; i < n; ++ i)
        std::cout << b[i] << ' ';*/
    std::sort (b + 0, b + n, cmp);
    for (int i = 0; i < n; ++ i)
        std::cout << b[i] << ' ';
    return ;
}int main ()
{
    //main;
    int T = 1; //cin >> T;
    while (T --)
        solve ();
    return 0;
}