cpp-course/modules/07_stl_containers/src/unordered_containers.cpp

#include "unordered_containers.hpp"

#include <algorithm>
#include <set>

namespace stl_containers {

auto first_unique(const std::vector<std::string>& words) -> std::string {
    auto s = std::set<std::string>();
    for (const auto& word : words) {
        if (!s.contains(word)) {
            s.insert(word);
        } else {
            s.erase(word);
        }
    }
    return s.empty() ? "" : *s.begin();
}

auto group_anagrams(const std::vector<std::string>& words)
    -> std::unordered_map<std::string, std::vector<std::string>> {
    auto groups = std::unordered_map<std::string, std::vector<std::string>>();
    for (const auto& word : words) {
        auto key = word;
        std::ranges::sort(key);
        groups[key].push_back(word);
    }
    return groups;
}

auto has_duplicate(const std::vector<int>& data) -> bool {
    auto s = std::set<int>{};
    for (auto i : data) s.insert(i);
    return s.size() != data.size();
}

}  // namespace stl_containers