DSA Placement Crash Course — 18 Patterns That Cover Most Interviews

You don't need 500 random LeetCode problems — you need to recognize which of ~18 underlying patterns a problem is testing, in under 60 seconds. This note gives you the exact recognition signals for Sliding Window, Two Heaps, Topological Sort, and 15 more, plus 3 fully worked examples and a company-round cheat table. Built for the last two weeks before placement season, not a semester-long DSA course.