Leetcode 2966. Divide Array Into Arrays With Max Difference

Partition the array (n is a multiple of 3) into n/3 triplets such that within every triplet the max minus min ≤ k, returning any valid set of triplets or an empty array if impossible. The core task is to decide feasibility and construct such triplets — typically approached by exploiting ordering (e.g., sorting) and greedy grouping.