You have learned basic greedy: sorting, two-pointer, single-pass decisions.
Now you will learn advanced techniques. In this section, I will show you Huffman coding (greedy with heaps), string rearrangement, and stack-based greedy problems. These problems require combining greedy thinking with other data structures. Each pattern appeared in previous sections separately. Here, you will combine heap manipulation with greedy decisions, stack operations with optimal digit selection, and frequency counting with rearrangement strategies.