#include <string>
#include <iostream>
#include <set>

namespace {

enum Dominoes : char {
    Dot = '.',
    L = 'L',
    R = 'R',
};

class Solution {
    public:
        std::string pushDominoes(std::string dominoes) {
            bool has_actions = true;
            
            while (has_actions) {
                size_t processed_dot = -1;
                size_t actions_found = 0;
                for (size_t i = 0; i < dominoes.size(); ++i) {
                    char d = dominoes[i];
                    if ((d == L || d == R) && processed_dot != i) {
                        ++actions_found;

                        bool left_dot = false;
                        bool right_dot = false;

                        if (i > 0 && (dominoes[i - 1] == Dot && processed_dot != (i - 1)))
                            left_dot = true;

                        if (i < (dominoes.size() - 1) && dominoes[i + 1] == Dot)
                            right_dot = true;

                        if (d == L && left_dot) {
                            if (i > 1 && dominoes[i - 2] == R && processed_dot != (i - 2))
                                --actions_found;
                            else {
                                dominoes[i - 1] = L;
                                processed_dot = (i - 1);
                            }
                        }

                        else if (d == R && right_dot) {
                            if (i < (dominoes.size() - 2) && dominoes[i + 2] == L)
                                --actions_found;
                            else {
                                dominoes[i + 1] = R;
                                processed_dot = (i + 1);
                            }
                        }

                        else
                            --actions_found;
                    }
                }
                if (!actions_found)
                    has_actions = false;
                
                std::cout << "step   " << dominoes << '\n';
            }
            return dominoes;
        }
    };
}

#include <gtest/gtest.h>

TEST(P838_1, 1) {
    std::string input = ".L.R...LR..L..";
    Solution s;
    auto result = s.pushDominoes(input);
    EXPECT_EQ(result, std::string("LL.RR.LLRRLL.."));
}