GT problems

List of problems
1.find shortest distance between two nodes in non-negatively weighted directed graph
2.find topological ordering of the nodes
3.find max flow in flow network
4.maximum matching in unweighted graph
5.matching in weighted bipartite graphs (an assignment problem )
6.find distances between all pairs of nodes in non-weighted directed graph
7.find minimum spanning tree for a connected weighted graph
8.test graph for bipartiteness
9.vertex cover problem