update Makefile, pretty the kruskal_mst.h

Author: fuli

Makefile

@@ -53,7 +53,8 @@ PROGRAMS =  m_based \
 			random_demo \
 			k-means_demo \
 			kmp_demo \
-			heap_sort_demo
+			heap_sort_demo \
+			kruskal_mst_demo
 
 all: $(PROGRAMS)
 

README.md

@@ -77,4 +77,4 @@
 ####贡献者 ( Contributors ) :  
     Samana :  for heavy work of MSVC compatability
     wycg1984: for K-Means
-    xmuliang: for HeapSort
+    xmuliang: for HeapSort, Kruskal MST

include/kruskal_mst.h

@@ -9,16 +9,20 @@
  *
  * Features:
  *
- *    Kruskal's algorithm is a greedy algorithm in graph theory that finds a minimum spanning tree for a connected weighted graph.
- *    This means it finds a subset of the edges that forms a tree that includes every vertex,
- *    where the total weight of all the edges in the tree is minimized. If the graph is not connected,
- *    then it finds a minimum spanning forest (a minimum spanning tree for each connected component).
- *    This algorithm first appeared in Proceedings of the American Mathematical Society, pp. 48–50 in 1956,
- *    and was written by Joseph Kruskal.
+ * Kruskal's algorithm is a greedy algorithm in graph theory that finds a 
+ * minimum spanning tree for a connected weighted graph.
+ * This means it finds a subset of the edges that forms a tree that includes 
+ * every vertex, where the total weight of all the edges in the tree is minimized. 
+ * If the graph is not connected, then it finds a minimum spanning forest 
+ * (a minimum spanning tree for each connected component).
+ *
+ * This algorithm first appeared in :
+ *     Proceedings of the American Mathematical Society, pp. 48–50 in 1956,
+ * and was written by Joseph Kruskal.
  *
  * http://en.wikipedia.org/wiki/Kruskal's_algorithm
  *
- *By Contibutor:xmuliang
+ * By Contibutor:xmuliang
  ******************************************************************************/
 
 #ifndef __KRUSKAL_MST_H__
@@ -59,8 +63,7 @@ namespace alg
 		/**
 		 * construct Kruskal's DataStrcuture by a given graph
 		 */
-		Kruskal(const Graph & g)
-		{
+		Kruskal(const Graph & g) {
 			INIT_LIST_HEAD(&m_pg);
 
 			Graph::Adjacent * a;
@@ -70,8 +73,7 @@ namespace alg
 			this->num_vertex=g.vertex_count();
 		}
 
-		~Kruskal()
-		{
+		~Kruskal() {
 			KruskalAdjacent * pa, *pan;
 			list_for_each_entry_safe(pa, pan, &m_pg, pa_node){
 				list_del(&pa->pa_node);
@@ -85,8 +87,7 @@ namespace alg
 		/**
 		 * add an adjacent list to Kruskal's graph
 		 */
-		void add_adjacent(const Graph::Adjacent & a)
-		{
+		void add_adjacent(const Graph::Adjacent & a) {
 			KruskalAdjacent * pa = new KruskalAdjacent(a.vertex(), a.num_neigh);
 			list_add_tail(&pa->pa_node, &m_pg);
 
@@ -100,8 +101,7 @@ namespace alg
 		 * lookup up a given id
 		 * the related adjacent list is returned.
 		 */
-		KruskalAdjacent * lookup(uint32_t id) const
-		{
+		KruskalAdjacent * lookup(uint32_t id) const {
 			KruskalAdjacent * pa;
 			list_for_each_entry(pa, &m_pg, pa_node){
 				if (pa->v.id == id) { return pa;}
@@ -123,8 +123,7 @@ namespace alg
 		 *
 		 * Output: Vnew and Enew describe a minimal spanning tree
 		 */
-		Graph * run()
-		{
+		Graph * run() {
 			UndirectedGraph * mst = new UndirectedGraph(); // empty Grapph
 
 			uint32_t mark[num_vertex];//    mark the different set
@@ -137,57 +136,47 @@ namespace alg
             uint32_t total_nodes=num_vertex;    //nodes of the Kruskal
 
 
-			while(true)
-			{
-			int weight = INT_MAX;
-			uint32_t best_to;
-            struct KruskalAdjacent * best_from;
+			while(true) {
+				int weight = INT_MAX;
+				uint32_t best_to;
+				struct KruskalAdjacent * best_from;
 
-            //choose the smallest edge from the original graph
-			list_for_each_entry(pa, &m_pg, pa_node){
-                if(!pa->heap.is_empty()&&pa->heap.min_key()<weight)
-                {
-                    weight = pa->heap.min_key();
-                    v = pa->heap.min_value();
-                    best_to = v->id;
-                    best_from = pa;
-                }
-			}
+				// choose the smallest edge from the original graph
+				list_for_each_entry(pa, &m_pg, pa_node){
+					if(!pa->heap.is_empty()&&pa->heap.min_key()<weight) {
+						weight = pa->heap.min_key();
+						v = pa->heap.min_value();
+						best_to = v->id;
+						best_from = pa;
+					}
+				}
 
-            //loop until the chosen edges to total_nodes-1
-			if (flag<(total_nodes-1)&&(weight != INT_MAX)) {
-
-					//if the node not been added,construct it
-					if((*mst)[best_from->v.id]==NULL)
-					{
-                        mst->add_vertex(best_from->v.id);
-                    }
-
-					if((*mst)[best_to]==NULL)
-					{
-                        mst->add_vertex(best_to);
-                    }
-
-                   //two nodes must belongs to set,to keep uncircle
-                    if(mark[best_from->v.id]!=mark[best_to])
-					{
-
-                        mst->add_edge(best_from->v.id, best_to, weight);
-
-                        uint32_t tmp=mark[best_to];
-                        for(uint32_t i=0;i<num_vertex;i++)
-                        {
-                            if(mark[i]==tmp)
-                                mark[i]=mark[best_from->v.id];
-                        }
-                        flag++;
-                    }
-
-					best_from->heap.delete_min();
-					lookup(best_to)->heap.delete_min();
+				// loop until the chosen edges to total_nodes-1
+				if (flag<(total_nodes-1)&&(weight != INT_MAX)) {
+						// if the node not been added,construct it
+						if((*mst)[best_from->v.id]==NULL) {
+							mst->add_vertex(best_from->v.id);
+						}
+
+						if((*mst)[best_to]==NULL) {
+							mst->add_vertex(best_to);
+						}
+
+					   // two nodes must belongs to set,to keep uncircle
+						if(mark[best_from->v.id]!=mark[best_to]) {
+							mst->add_edge(best_from->v.id, best_to, weight);
+
+							uint32_t tmp=mark[best_to];
+							for(uint32_t i=0;i<num_vertex;i++) {
+								if(mark[i]==tmp)
+									mark[i]=mark[best_from->v.id];
+							}
+							flag++;
+						}
+
+						best_from->heap.delete_min();
+						lookup(best_to)->heap.delete_min();
 				} else break;
-
-
 			}
 
 			return mst;
@@ -196,8 +185,7 @@ namespace alg
 		/**
 		 * print the KruskalGraph
 		 */
-		void print()
-		{
+		void print() {
 			struct KruskalAdjacent * pa;
 			printf("Kruskal Graph: \n");
 			list_for_each_entry(pa, &m_pg, pa_node){