Breadth-First Search
Explore level by level from a starting point, the go-to way to find the shortest path in an unweighted graph.
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Depth-First Search
Explore as far as possible down one path before backtracking, used to walk trees, graphs, and grids.
Depth-First Search Practice Problems
Easy
3 problems- 32easy
Flood Fill
Change the color of a connected region in an image, starting from one pixel.
- 33easy
Maximum Depth of Binary Tree
Find the number of nodes along the longest path from the root of a tree to a leaf.
- 210easy
Path Sum
Check whether a binary tree has a root-to-leaf path that adds up to a target sum.
Medium
3 problemsHard
2 problemsRelated concepts
Dijkstra's Algorithm
Find the shortest path from a starting node to every other node in a graph where edges have non-negative weights.
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Bellman-Ford Algorithm
Find the shortest path from a starting node even when some edges have negative weights, and detect negative cycles.
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Topological Sort
Order the nodes of a graph so every task comes after everything it depends on, used for scheduling and build order.
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Union-Find (Disjoint Set)
Track which nodes belong to the same group and merge groups quickly, used to detect cycles and build networks.
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Kruskal's Algorithm
Build the cheapest network connecting all nodes by adding the smallest edges first, skipping any that form a cycle.
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