About This Pattern
Master the Topological Sort pattern by practicing these problems organized by difficulty.Focus on the Key Signals - these are the indicators that tell you when to use this pattern.
Medium (1)
Course Schedule II
Return ordering of courses to take (topological sort).
Key Signals:
DFS post-orderOr BFS with in-degreeReturn reverse order
Hard (1)
Alien Dictionary
Derive the order of characters in an alien language from sorted words.
Key Signals:
Build graph from adjacent wordsTopological sortDetect invalid