#include <stdio.h>
#include <string.h>
#include <stdbool.h>

#define SIZE_LINES 1024
#define SIZE 256

typedef struct {
    char text[SIZE];
    bool isAnswer;
    int yes;   //ekvivalent 'left' (alebo 'a')
    int no;   //ekvivalent 'right' (alebo 'n')
} Node;

Node tree[SIZE];
char lines[SIZE_LINES][SIZE];

//pomocne premeny
int lineCount = 0;
int indexLine = 0;
int nodeCount = 0;
int answerCount = 0;
bool isTreeBroken = false;

//pomocna konstanta
const int invalidIndex = -1;

// vytvorii binarny strom na zakl. vstupu
//** VRATI -> Bud cislo > 0 (Platny Koren) ALEBO stav '-1' (Neplatny index korenu, cize koniec stromu)
int buildATree()
{
    if (indexLine >= lineCount)
    {
        isTreeBroken = true;
        return -1;
    }

    char *line = lines[indexLine];
    indexLine += 1;
    //pomocny index
    int current = nodeCount;
    nodeCount += 1;

    if (line[0] == '*') 
    {
        tree[current].isAnswer = true;
        strcpy(tree[current].text, line + 1);
        tree[current].yes = invalidIndex;
        tree[current].no = invalidIndex;

        answerCount += 1;
        return current;
    }

    tree[current].isAnswer = false;
    strcpy(tree[current].text, line);

    //rekurzivne vytvorii dalsie 'nodes' (uzly po slovensky) na na zaklade vycitanych odpovedi z standard inputu
    tree[current].yes = buildATree(); // 'a' 
    tree[current].no  = buildATree(); // 'n'

    //kontrola - jedna otazka musii mat dve deti (AK NIE vyhodi chybu)
    if (tree[current].yes == -1 || tree[current].no == -1)
    {
        treeIsBroken = true;
    }

    return current;
}

void goThroughTheTree(int rootIndex) 
{
    //pomocne premeny
    int current = rootIndex;
    char input = '0'; // '0' = ako keby nic / NULL

    while (current != -1) 
    {
        if (tree[current].isAnswer) 
        {
            printf("*%s\n", tree[current].text);
            printf("Koniec\n");
            return;
        }

        printf("%s\n", tree[current].text);

        //nacitanie odpovedi (jeden char)
        if (scanf(" %c", &input) != 1) 
        {
            printf("Koniec vstupu\n");
            return;
        }

        if (input == 'a') 
        {
            current = tree[current].yes;
        } 
        else if (input == 'n') 
        {
            current = tree[current].no;
        } 
        else if (input != 'n' || input != 'a')
        {
            printf("Nerozumiem\n");
            return;
        }
    }
}

int main() 
{
    char buffer[SIZE];

    //null-terminovanie
    buffer[0] = '\0';

    // citanie vstupu
    while (fgets(buffer, SIZE, stdin)) 
    {
        //prestane citat vstup, ak je NEPLATNY (rovna sa Newline symbolu, resp. prazdny riadok) 
        if (strcmp(buffer, "\n") == 0)
        {
            break;
        }
        //ALEBO ak sa nenacital riadok vobec (buffer je uplne prazdny, (resp prvy prvok je null terminator))
        if (buffer[0] == '\0')
        {
            break;
        }
        //nahradi NewLine symbol za null terminator (Newline sa prida naspat potom na konci programu)
        buffer[strcspn(buffer, "\n")] = '\0';
        
        strcpy(lines[lineCount], buffer);
        lineCount += 1;
    }
    
    //zisk. korena
    int root = buildATree();

    printf("Expert z bufetu to vie.\n");
    if (treeIsBroken || indexLine != lineCount || answerCount == 0)
    {
        printf("Chybna databaza\n");
    }
    else
    {
        printf("Pozna %d druhov ovocia a zeleniny.\n", answerCount);
        printf("Odpovedajte 'a' pre prvu moznost alebo 'n' pre druhu moznost.\n");

        goThroughTheTree(root);
    }

    return 0;
}