// graph.c: set up data structure for graph
// Uses adjacency list representation
#include <stdio.h>
#include <stdlib.h>
#define GRAPHSIZE 48

struct graphnode { // node for graph's vertex
   struct edgenode* firstedgenode; // to entire adj. list
   // other vertex info here
};

struct edgenode { // holds graph's edge info
   int vertexnum; // head end of edge
   int edgedist; // data: here it's distance
   struct edgenode* nextedgenode; // next edge
   // other edge info here
};

void printgraph(struct graphnode* graph[], int count);
struct graphnode* newgraphnode();
struct edgenode* newedgenode(int num, struct edgenode* node, int dist);
void insert(struct graphnode* graph[], int num1, int num2, int dist);
int edgedistance(struct graphnode* graph[], int v1, int v2);
int pathlength(struct graphnode* graph[], int path[], int len);

int main() {
   // three Hamiltonian paths
   int ham1[] =
       {47,45,42,44,46,43,41,40,39,37,33,38,
        34,28,29,24,21,16,10,15,20,23,27,32,
        26,36,35,31,30,25,22,18,17,11, 7,12,
         8,13,19,14, 9, 5, 4, 0, 2, 1, 6, 3};
   int ham2[] =
       {47,45,42,44,46,43,41,40,38,39,37,32,
        36,35,31,30,25,22,17,11,12,18,26,27,
        33,34,29,28,23,19,13,14,20,24,21,15,
        16,10, 6, 5, 9, 8, 7, 4, 1, 0, 2, 3};
   int ham3[] =
       {47,45,42,44,46,43,41,40,39,37,33,32,
        36,35,31,30,25,26,27,28,23,20,19,18,
        22,17,11,12,13,14,15, 9, 8, 7, 4, 5,
         1, 0, 2, 3, 6,10,16,21,24,29,34,38};

   struct graphnode* graph[GRAPHSIZE];
   int i;
   int num1, num2, num;
   for(i = 0; i < GRAPHSIZE; i++) graph[i] = newgraphnode();

   FILE *infile;
   infile = fopen("capsdist.txt", "r");
   if (infile == NULL) {
      fprintf(stderr, "Can't open %s\n", "source.txt");
      exit(1);
   }
   while (fscanf(infile, "%i%i%i", &num1,&num2,&num) != EOF) {
      // carry out insertions, both directions
      insert(graph, num1, num2, num);
      insert(graph, num2, num1, num);
   }
   printgraph(graph, GRAPHSIZE);
   printf("Path length: %i\n", pathlength(graph, ham3, 48));
}

struct graphnode* newgraphnode(){
   // may want to use this to create graphnodes
}

struct edgenode* newedgenode(int num, struct edgenode* node,
      int dist) {
   // may want to use this to create edgenodes
}
  
void insert(struct graphnode* graph[], int num1, int num2, int dist){
   // patch the new node in at the start
   if (graph[num1] -> firstedgenode == NULL) {
      // create new adjacency list, with
      // a node for num2, its only entry
   }
   else {
      // patch in a node for num2 at the
      // start of the existing adj list
   }
}
      
void printgraph(struct graphnode* graph[], int count) {
   // print the data in the graph,
   // perhaps in the form below
}

int edgedistance(int v1, int v2) {
   // if (v1, v2) is an edge
   // return edgeDist of this edge
   // otherwise return -1
}

int pathlength(struct graphnode* graph[], int path[], int len) {
   // calculate and return the length
   // of the path specified by the input
   // parameter.  If the "path" includes
   // a non-edge return -1
}