Please Explain Difficulty Levels

Please explain the difficulty levels in the practice problems section. The levels from easy to challenge are understandable, but “peer” seems to be easier than the easy level even though it is placed after challenge. Is this true? please clarify.

After each contest that is held by codechef the problems are added to easy/medium/hard depending on the difficulty of the problems. Every long contest has a partial marking problem that is added to the challenge section. Problems from external contests which are not directly conducted by codechef are added to peer section, it includes problems of all difficulties.