C Kruskal’s algorithm – Reference

Image Description
Kruskal Algorithm 1.svg AD and CE are the shortest arcs, with length 5, and AD has been arbitrarily chosen, so it is highlighted.
Kruskal Algorithm 2.svg CE is now the shortest arc that does not form a cycle, with length 5, so it is highlighted as the second arc.
Kruskal Algorithm 3.svg The next arc, DF with length 6, is highlighted using much the same method.
Kruskal Algorithm 4.svg The next-shortest arcs are AB and BE, both with length 7. AB is chosen arbitrarily, and is highlighted. The arc BD has been highlighted in red, because there already exists a path (in green) between B and D, so it would form a cycle (ABD) if it were chosen.
Kruskal Algorithm 5.svg The process continues to highlight the next-smallest arc, BE with length 7. Many more arcs are highlighted in red at this stage: BC because it would form the loop BCE, DE because it would form the loop DEBA, and FE because it would form FEBAD.
Kruskal Algorithm 6.svg Finally, the process finishes with the arc EG of length 9, and the minimum spanning tree is found.