# Session 8 — Recursion Sheet, Backtracking & Number Bases

## Problems
- Recursion sheet: https://codeforces.com/group/MWSDmqGsZm/contest/223339
- Lucky numbers: https://codeforces.com/problemset/problem/96/B
- Number Bases (base 2/10/Hex): https://codeforces.com/problemset/problem/602/A

## Concepts covered
Backtracking, introduced through the Lucky Numbers problem (see scripts
below). See `/Concept_Resources/backtracking.md` for reference material.

## Scripts
- `scripts/number_base_student3_buggy.cpp` — has a bug (`npow` undefined/unused function)
- `scripts/number_base_student4_working.cpp` — working version
- `scripts/lucky_numbers_backtracking_student1.cpp` — reference solution
- `scripts/lucky_numbers_backtracking_student2.cpp` — alternate solution