C - +/- Rectangle
E - Connected?
Yandex.Algorithm Open 2011: Qualification 1 B. Sequence Formatting
Yandex.Algorithm Open 2011: Qualification 1 C. Average Score
Yandex.Algorithm 2011: Qualification 2 B. Sets
Codeforces Beta Round 72 (Div. 2 Only) C. Biathlon
Codeforces Beta Round 76 (Div. 1 Only) A. Frames
Check DFS
Celsius to Fahrenheit
Base K Xor