Dfs tree example. Oct 30, 2025 · Depth-First Search (DFS) is a method used to explore all the nodes in a tree by going as deep as possible along each branch before moving to the next one. The algorithm starts at the root node (selecting some arbitrary node as the root node in the case of a graph) and explores as far as possible along each branch before backtracking. DFS makes use of Stack for storing the visited nodes of the graph / tree. For example, in the DFS tree above, the edge between 6 and 2 isn't a bridge, because even if we remove it, the back-edge between 3 and 8 holds the graph together. Python Interview Question at - Solve the Maximum Depth of Binary Tree problem in Python. Depth First Search ( DFS ) Algorithm Key points DFS is an algorithm for traversing a Graph or a Tree. Exhaustive search with pruning (permutations, subsets, N-Queens, sudoku solver, word search) - solved with Backtracking. There are many ways of traversing trees, and they’re usually classified based on the order that the traversal occurs. They can also be broadly categorized based on the direction of traversal as depth-first (vertical) or breadth-first (horizontal) traversal. Unlike linear data structures such as arrays, linked lists, or queues (which have only one logical way of traversal), trees offer multiple ways to traverse their nodes.