Add comprehensive Two Pointers technique documentation

Co-authored-by: pertrai1 <442374+pertrai1@users.noreply.github.com>

Author: Copilot

docs/README.md

@@ -7,3 +7,10 @@
 - Maintain a window over an array/string while expanding and shrinking based on constraints.
 - Used for longest substring problems, frequency constraints, and streaming aggregates.
 - [Technique Details](techniques/SLIDING_WINDOW.md)
+
+### Two Pointers Technique
+
+- Use two pointers to traverse data structures efficiently, eliminating nested loops.
+- **Opposite Direction**: Pointers start at opposite ends and converge (e.g., Two Sum, palindrome checking).
+- **Same Direction**: Pointers move in parallel at different speeds (e.g., remove duplicates, fast/slow cycle detection).
+- [Technique Details](techniques/TWO_POINTERS.md)