1 #include <stdio.h>
   2 
   3 #define nodes 5
   4 #define edges 8
   5 
   6 char edge[nodes][nodes] = {
   7     { 0, 1, 0, 1, 1 },
   8     { 1, 0, 1, 1, 1 },
   9     { 0, 1, 0, 1, 0 },
  10     { 1, 1, 1, 0, 1 },
  11     { 1, 1, 0, 1, 0 }
  12 };
  13 
  14 char path[edges + 2] = "1xxxxxxxx";
  15 
  16 void move(unsigned int i, unsigned int level)
  17 {
  18     if (level > edges) {
  19         printf("%s\n", path);
  20     } else {
  21         unsigned int j;
  22         for (j = 0; j < nodes; ++j) {
  23             if (edge[i][j]) {
  24                 edge[i][j] = 0;
  25                 edge[j][i] = 0;
  26 
  27                 path[level] = '1' + j;
  28                 move(j, level + 1);
  29 
  30                 edge[j][i] = 1;
  31                 edge[i][j] = 1;
  32             }
  33         }
  34     }
  35 }
  36 
  37 int main(void)
  38 {
  39     move(0, 1);
  40     return 0;
  41 }