The best programmers are not marginally better than merely good ones. They are an order-of-magnitude better, measured by whatever standard: conceptual creativity, speed, ingenuity of design, or problem-solving ability. Randall E. Stross
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