【Codeforces 512D】Fox And Travelling
【AtCoder Grand Contest 037 E】Reversing and Concatenating
【AtCoder Grand Contest 037 D】Sorting a Grid
【AtCoder Grand Contest 030 C】Coloring Torus
【AtCoder Grand Contest 029 C】Lexicographic constraints
【Codeforces 704E】Iron Man
【Codeforces 643D】Bearish Fanpages
【CQOI2017】老 C 的方块
【AtCoder Grand Contest 020 F】Arcs on a Circle
【AtCoder Grand Contest 021 E】Ball Eat Chameleons