1 files changed, 128 insertions, 0 deletions
diff --git a/src/utils/dset.c b/src/utils/dset.c
new file mode 100644
index 0000000..acb6bc8
--- /dev/null
+++ b/src/utils/dset.c
@@ -0,0 +1,128 @@
+/**
+ *  This program is free software: you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  (c) Vincenzo Nicosia 2009-2017 -- <v.nicosia@qmul.ac.uk>
+ * 
+ *  This file is part of NetBunch, a package for complex network
+ *  analysis and modelling. For more information please visit:
+ *
+ *             http://www.complex-networks.net/
+ *
+ *  If you use this software, please add a reference to 
+ *
+ *               V. Latora, V. Nicosia, G. Russo             
+ *   "Complex Networks: Principles, Methods and Applications"
+ *              Cambridge University Press (2017) 
+ *                ISBN: 9781107103184
+ *
+ ***********************************************************************
+ *
+ *  This files implements a disjoint-set data structure, where nodes
+ *  labels are integers.
+ *
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "dset.h"
+
+void dset_makeset(dset_t *ds){
+  
+  if (*ds == NULL){
+    *ds= malloc(sizeof(dset_elem_t));
+  }
+  (*ds)->parent = *ds;
+  (*ds) -> rank = 0;
+}
+
+void dset_destroy(dset_t ds){
+  free(ds);
+}
+
+
+void dset_makeset_id(dset_t *ds, int id){
+  
+  dset_makeset(ds);
+  (*ds)->id = id;
+}
+
+
+dset_t dset_find(dset_t ds){
+  if (ds -> parent == ds){
+    return ds;
+  }
+  else return dset_find(ds->parent);
+}
+
+void dset_union(dset_t s1, dset_t s2){
+  dset_t r1, r2;
+
+  r1= dset_find(s1);
+  r2= dset_find(s2);
+  r2->parent = r1;
+}
+
+
+void dset_union_opt(dset_t s1, dset_t s2){
+  dset_t r1, r2;
+
+  r1= dset_find(s1);
+  r2= dset_find(s2);
+  if (r1 == r2){
+    return;
+  }
+  
+  if (r1->rank < r2->rank){
+    r1->parent = r2;
+  }
+  else if (r1->rank > r2->rank){
+    r2->parent = r1;
+  }
+  else{
+    r2->parent = r1;
+    r1->rank += 1;
+  }
+}
+
+
+dset_t dset_find_opt(dset_t ds){
+  if (ds->parent != ds){
+    ds->parent = dset_find_opt(ds->parent);
+  }
+  return ds->parent;
+}
+
+
+int dset_find_id(dset_t ds){
+  
+  dset_t res;
+
+  res = dset_find(ds);
+  
+  return res->id;
+}
+
+
+int dset_find_id_opt(dset_t ds){
+  
+  dset_t res;
+
+  res = dset_find_opt(ds);
+  
+  return res->id;
+}
+