January Challenge 2015
Chef and A Large Permutation, Chef and Stones, Sereja and Votes, One Dimensional Kingdoms, Gcd Queries
February Challenge 2015
Chef and Chain, Chef and Equality
March Challenge 2015
Chef and Notebooks, Sign Wave
April Challenge 2015
Count Sequences, Chef and Piano Scales, Broken Telephone, Chef and Interview
May Challenge 2015
Devu and binary String, Chef and Prime Divisors, Set Difference , Chef and new recipe, Chef and Cake
June Challenge 2015
Steady tables, Chef and Polygons, Chef and His Friend, Chef and Memory Limit
July Challenge 2015
Addition and Multiplication, Sereja and Game 2, Bread, MasterChef, Na2a and lucky stone, Chef and Cube, Rohith and Circles
August Challenge 2015
Way Out, Aditi and Magic Trick, Cooking Machine, Gravity Guy
August Cook-Off 2015
Chef and the XORed Number , Chef and the Wildcard Matching
September Mega Cook-Off 2015
Reign 2, Forgotten Language, Super Numbers, Stacks
India