problema 3. domino pieces

domino.c

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

typedef struct {
   int x1,
       x2;

} Domino;

int totalChains = 0;

/*
piece1: (1,2)
piece2: (3,2)
piece3: (4,1)
piece4: (3,7)
piece5: (5,4)

(2,1) -> (1,4) -> (4,5)
*/
bool canConnect(Domino piece1, Domino piece2) {

    return (piece1.x1 == piece2.x1) || (piece1.x1 == piece2.x2) ||
           (piece1.x2 == piece2.x1) || (piece1.x2 == piece2.x2);
}

void printChain(Domino dominoes[], int chain[], int chainSize) {

    totalChains++;

    printf("Lantul %d ",totalChains);

    for(int i = 0; i < chainSize; ++i) {

         int idx = chain[i];
         printf("(%d,%d)", dominoes[idx].x1, dominoes[idx].x2);

         if(i < chainSize - 1) {
           printf(" -> ");
         }
     }

     printf("\n");
}

void findDominoChains(Domino dominoes[], int n, int m, bool used[], int currentChain[], int chainSize) {

   if(chainSize == m) {
       printChain(dominoes, currentChain, chainSize);
       return;
   }

   for(int i = 0; i < n; ++i) {

      if( used[ i ]) { 

          continue;
      }

      bool canAdd = false;

      if(chainSize == 0) {

         canAdd = true;

      } else {

        int lastIndex = currentChain[chainSize - 1];

             canAdd = canConnect(dominoes[lastIndex], dominoes[i]);
      }

      if( canAdd ) {

          used[ i ] = true;

          currentChain[chainSize] = i;

          findDominoChains(dominoes, n, m, used, currentChain, chainSize + 1);

          used[ i ] = false;
      }

   }

}



int main(int argc, char const *argv[]) {

  int n, m;

  printf("Introduceti numarul de piese de domino disponibile (n):");
  scanf("%d", &n);

  printf("Introduceti numarul de piese pentru lant (m): ");
  scanf("%d", &m);

  if(m > n) {
     printf("Error: m cannot be > n");
     return 1;
  }

  if(m <= 0 || n <= 0) {
    printf("Error: n, m > 0");
    return 1;
  }

  Domino *dominoes = (Domino*)malloc(n * sizeof(Domino));

  printf("Introduceti piesele de domino ca perechi (x1,x2):\n");

  for(int i = 0; i < n; ++i) {
      printf("Piece %d: ", i + 1 );
      scanf("%d %d", &dominoes[i].x1, &dominoes[i].x2);
  }

  printf("Piesele de domino introduse: \n");

  for(int i = 0; i < n; ++i) {
    printf("Piece %d:  (%d, %d)\n", i + 1, dominoes[i].x1, dominoes[i].x2);
  }

  bool *used = (bool*)calloc(n, sizeof(bool));

  int *currentChain = (int*)malloc(m * sizeof(int));

  totalChains = 0;

  printf("Cautam toate lanturile cu %d piese: \n", m);
  printf("------------------------------------\n");

  findDominoChains(dominoes, n, m, used, currentChain, 0);
  printf("------------------------------------\n");

  if(totalChains == 0){
    printf("Nu s-au gasit lanturi valide!\n");
  }else {
    printf("Total lanturi gasite: %d", totalChains);
  }
  //free(dominoes);
  //free(used)
  //free(currentChain)

  return 0;
}