CS153/hw6/hw5programs/jacbrad_kruskal.oat

struct Edge {
  int u;
  int v;
  int weight
}

int compare(Edge e1, Edge e2) {
  return e1.weight - e2.weight;
}

void sort((Edge, Edge) -> int cmp, int len, Edge[] list) {

  for(var i = 1; i < len; i = i + 1;){
    var j = i - 1;
    var toswap = list[i];
    while(j >= 0) {
      if(cmp(list[j], toswap) > 0) {
        var temp = list[j];
        list[j] = list[j+1];
        list[j+1] = temp;
        j = j - 1;
      }
      else { 
        j = -1;
      }
    }
  }
  return;
}


int[] create_ufind(int len)
{
  var arr = new int[len];
  for(var i = 0; i < len; i = i + 1;)
  {
    arr[i] = i;
  }
  return arr;
  
}

void union(int[] comps, int u, int v)
{
  var cU = find(comps, u);
  var cV = find(comps, v);

  if(cU == cV)
  {
    return;
  }

  comps[cU] = cV;
  return;
}

int find(int[] comps, int u)
{
  var root = u;
  while(root != comps[root])
  {
    root = comps[root];
  }

  while(u != root)
  {
    var parent = find(comps, comps[u]);
    comps[u] = root;
    u = parent;

  }

  return root;

}

Edge[] findMST(Edge[] edges, int m, int n) {
  sort(compare, m, edges);
  var uf = create_ufind(n);
  var result = new Edge[n-1];
  var size = 0;
  var count = 0;

  while(size < n - 1){

    if(find(uf, edges[count].u) != find(uf, edges[count].v)){
       result[size] = edges[count];
       union(uf, edges[count].u, edges[count].v);
       size = size + 1;
    }

    count = count + 1;
  }
  return result;
}


int program (int argc, string[] argv) {
  var e1 = new Edge {u = 1; v = 2; weight = 3};
  var e2 = new Edge {u = 0; v = 1; weight = 20};
  var e3 = new Edge {u = 1; v = 4; weight = 1};
  var e4 = new Edge {u = 2; v = 4; weight = 5};
  var e5 = new Edge {u = 3; v = 4; weight = 6};
  var e6 = new Edge {u = 2; v = 3; weight = 4};

  var edges = new Edge[]{e1, e2, e3, e4, e5, e6};
  var mst = findMST(edges, 6, 5);
  
  for(var i = 0; i < 4; i = i + 1;){
    print_string("(");
    print_int(mst[i].u);
    print_string(",");
    print_int(mst[i].v);
    print_string(",");
    print_int(mst[i].weight);
    print_string(") ");
  }
  print_string("=");
  return 0;
}