Instructions for running Code:

The programs can be run by redirecting an input file to the standard input example: java filename<input.txt
Kruskal's algorithm assumes that the input provided is a weighted undirected graph.
Dijkstra's, floyd warshall's all pair shortest path and transitive closure assume that the input provided is a weighted directed graph

Also, sample inputs for directed and undirected graphs have been given the input folder. 
They have been named as: 
[directed]/[undirected]_[no_of_vertices]_[no_of_edges]
for example dir_40_360 says that the graph is directed with 40 vertices and 360 edges