> I was thinking of Quicksort, where j moves left until it meets i, and missed the fact that they both move in the same direction and i runs through the entire

> I was thinking of Quicksort, where j moves left until it meets i, and missed the fact that they both move in the same direction and i runs through the entire list. You were thinking of Hoare partitioning. Quicksort can use either Hoare or Lomuto (or any other) partitioning algorithm.