(Latest Revision: Thu Mar 18 13:38:54 PDT 2021 ) mstProbSoln.txt

mstProbSoln.txt




Original list - the edges of a connected, undirected graph
{6, 7}  1  
{1, 6}  2
{1, 7}  3  
{4, 7}  4  
{1, 4}  5  
{5, 7}  6  
{4, 5}  7  
{5, 6}  8  
{2, 3}  9  
{3, 5} 10  
{2, 5} 11
{1, 2} 12
{2, 7} 13
{3, 6} 14
{2, 4} 15

Execution of Kruskal's Algorithm,
showing the disjoint sets

{6, 7}  1  accept {6,7} {1} {2} {3} {4} {5}
{1, 6}  2  accept {1,6,7} {2} {3} {4} {5}
{1, 7}  3  reject {1,6,7} {2} {3} {4} {5}
{4, 7}  4  accept {1,4,6,7} {2} {3} {5}
{1, 4}  5  reject {1,4,6,7} {2} {3} {5}
{5, 7}  6  accept {1,4,5,6,7} {2} {3}
{4, 5}  7  reject {1,4,5,6,7} {2} {3}
{5, 6}  8  reject {1,4,5,6,7} {2} {3}
{2, 3}  9  accept {1,4,5,6,7} {2,3}
{3, 5} 10  accept {1,2,3,4,5,6,7}
{2, 5} 11
{1, 2} 12
{2, 7} 13
{3, 6} 14
{2, 4} 15

Kruskal List
The 6 accepted edges that form the min cost spanning tree, 
in the order found, are:
{6, 7}  1
{1, 6}  2
{4, 7}  4
{5, 7}  6
{2, 3}  9
{3, 5} 10

The cost of the tree is 1+2+4+6+9+10 = 32


Execution of Prim's Algorithm, using the ordered list as an aid

{6, 7}  1  Prim #2 (cheapest edge leaving S={1,6}) Now S = {1,6,7}
{1, 6}  2  Prim #1 (cheapest edge leaving S={1}) Now S = {1,6}
{1, 7}  3  
{4, 7}  4  Prim #3 (cheapest edge leaving S={1,6,7}) Now S = {1,4,6,7}
{1, 4}  5  
{5, 7}  6  Prim #4 (cheapest edge leaving S={1,4,6,7}) Now S = {1,4,5,6,7}
{4, 5}  7  
{5, 6}  8  
{2, 3}  9  Prim #6 (cheapest edge leaving S={1,3,4,5,6,7}) Now S = {1,2,3,4,5,6,7}  
{3, 5} 10  Prim #5 (cheapest edge leaving S={1,4,5,6,7}) Now S = {1,3,4,5,6,7}
{2, 5} 11
{1, 2} 12
{2, 7} 13
{3, 6} 14
{2, 4} 15

Prim List
The 6 accepted edges that form the min cost spanning tree, 
in the order found, are:
{1, 6}  2
{6, 7}  1
{4, 7}  4
{5, 7}  6
{3, 5} 10
{2, 3}  9

The cost of the tree is 2+1+4+6+10+9 = 32