Patterns

Problem-solving patterns for SDE-3 DSA interviews. Use with SDE3_DSA_ROADMAP.md.

• LeetCode Patterns — Condensed guide to standard patterns (array, search, linked list, tree, graph, DP, backtracking).

• Two Pointers & Sliding Window — When to use opposite-end vs same-direction two pointers; variable vs fixed sliding window; pattern recognition.

• DP Advanced Patterns — 16 DP patterns (Fibonacci, Knapsack, LIS, LCS, Interval, Tree, Bitmask, Digit, etc.).

• Coding Patterns — Additional pattern reference.

• Common Patterns / Common Patterns (Theta) — Alternative pattern lists.