PPCodeChallenge

PayPal Code challenge was organized the first time in 2015, with over 100 people registered.

Contest information can be found here.

List of problems used by ascending order of difficulty:

1. HQ9+ (implementation skill)
2. Black White (basic implementation skill)
3. Four (Smart brute force)
4. Moving Stone (Greedy)
5. Pet Detective (BFS/Dijkstra)
6. Jumping Around (math, probability, dynamic programming)
7. Inversion (2D Fenwick tree / divide & conquer + Fenwick tree)

Backup problem:

1. Magic square