The first 90 percent of the code accounts for the first 90 percent of the development time...The remaining 10 percent of the code accounts for the other 90 percent of the development time. Tom Cargill
Graph and tree nodes can be traversed using the backtracking technique. Depth-first search (DFS) is an algorithm for traversing or searching tree or graph data structures. DFS takes less memory compare than Breadth-first search and not necessary to store all of the child pointers at each level.
DFS technique used in web-crawling, Finding connected components, Topological sorting, Finding the bridges of a graph, Finding strongly connected components, Solving puzzles with only one solution, such as mazes, maze generation may use a randomized depth-first search, Finding connectivity in graphs.
Visits from source to destination using DFS: A->B->C->D->E