选出对称串并排序输出

Question

选出对称串并按长度排列输出，请问要怎么才能按长度排列输出？可以的话麻烦说一下详细易懂解题思路

Answer 1

#include <iostream>
#include <string>
#include <iterator>
#include <vector>
#include <algorithm>
#include <ranges>

using namespace std;

bool symmetric(const string &s)
{
    if (s.empty())
        return true;
    auto p = s.begin();
    auto q = --s.end();
    while (p < q)
    {
        if (*p != *q)
            return false;
        ++p;
        --q;
    }
    return true;
}

int main()
{
    vector<string> strs;
    for (const auto &s : ranges::subrange(istream_iterator<string>(cin), istream_iterator<string>()) | ranges::views::filter(symmetric))
        strs.push_back(s);
    sort(strs.begin(), strs.end(), [](const auto &lhs, const auto &rhs)
         { return lhs.length() < rhs.length(); });
    copy(strs.begin(), strs.end(), ostream_iterator<string>(cout, "\n"));
    return 0;
}

$ g++ -Wall -std=c++20 main.cpp
$ ./a.out
123321
123454321
123
312
sdfsdfd
121212
\\dd\\

123321
\\dd\\
123454321