Two Pointers

1. Pair With Target Sum (Two Sum)
2. Remove Duplicates
3. Remove Target
4. Squaring a Sorted Array
5. Triplet Sum to Zero
6. Triplet Sum Close to Target
7. Triplets With Smaller Sum
8. Count Triplets Within a Range
9. Dutch National Flag Problem (Sort an Array of 0s, 1s, and 2s)
10. Backspace Compare String
11. Minimum Window Sort

Sliding Window Pattern

Merge Intervals & Heap

1. Merge Intervals
2. Insert Interval
3. K Largest Numbers in the Array
4. Kth Smallest Number in the Array
5. K Closest Points to the Origin
6. Reorganize String
7. Reorganize String II