LeetCode/cpp/determine-if-two-strings-are-close.cpp

#include <algorithm>
#include <array>
#include <string>

class Solution {
    using freq_t = std::array<std::size_t, 26>;

    freq_t freqs(const std::string& word)
    {
        freq_t f { 0 };

        for (auto c : word) {
            f[c - 'a']++;
        }

        return f;
    }

    int mask(const freq_t& f)
    {
        int m = 0;

        for (auto c : f) {
            m = (m << 1) | (c > 0);
        }

        return m;
    }

public:
    bool closeStrings(std::string word1, std::string word2)
    {
        auto f1 = freqs(word1);
        auto m1 = mask(f1);
        std::sort(f1.begin(), f1.end());

        auto f2 = freqs(word2);
        auto m2 = mask(f2);
        std::sort(f2.begin(), f2.end());

        return m1 == m2 && f1 == f2;
    }
};