Sliding Window

Two Pointers

Fast & Slow Pointers

Merge Intervals

Cyclic Sort

In-place reversal of a linked list

Tree breadth-first search

Tree depth-first search

Two heaps

Modified Binary Search

Top ‘K’ elements

K-way merge

Subsets

Topological Sort (Graph)

0/1 Knapsack DP

Bitwise XOR

Prefix Sum

Union Find

Miscellaneous