Depth-First Search
Explore as far as possible down one path before backtracking, used to walk trees, graphs, and grids.
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Breadth-First Search
Explore level by level from a starting point, the go-to way to find the shortest path in an unweighted graph.
Breadth-First Search Practice Problems
Easy
2 problemsMedium
4 problems- 39medium
Binary Tree Level Order Traversal
Return the values of a tree grouped level by level, from top to bottom.
- 40medium
Rotting Oranges
Find the minimum time for rot to spread to every fresh orange in a grid.
- 41medium
01 Matrix
Find the distance from every cell in a grid to its nearest zero.
- 42medium
Shortest Path in Binary Matrix
Find the shortest path from the top-left to the bottom-right cell of a grid.
Hard
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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