Graph traversals

A graph traversal means to visit all the vertices of the graph while keeping track of which nodes or vertices have already been visited and which ones have not. A graph traversal algorithm is efficient if it traverses all the nodes of the graph in the minimum possible time. Graph traversal, also known as a graph search algorithm, is quite similar to the tree traversal algorithms like preorder, inorder, postorder, and level order algorithms; similar to them, in a graph search algorithm we start with a node and traverse through edges to all other nodes in the graph.

A common strategy of graph traversal is to follow a path until a dead end is reached, then traverse back up until there is a point where we meet an alternative path. We can also iteratively move from one node to another in order to traverse the full graph or part of it. Graph traversal algorithms are very important in answering many fundamental problems—they can be useful to determine how to get...