January Challenge 2015
Queries on the String, Sereja and Number Division 2, Chef and Stones, Sereja and Votes, One Dimensional Kingdoms
February Challenge 2015
Chef and Chain, Time to Study Graphs with Chef, Chef and Strange Formula, Chef and Strings, Let us play with rank list, Jigsaw Puzzle Solving, Chef and Equality
March Challenge 2015
Count Substrings, Sign Wave
April Challenge 2015
Count Sequences, Chef and Interview, Broken Telephone, Division of Lands, Chef and Piano Scales
May Challenge 2015
Devu and binary String, Chef and Prime Divisors, Set Difference , Chef and new recipe, Chef and Cake
