Group equal consecutive values into sublists

Summary

Group runs of consecutive equal values in a list into sublists, preserving order and element types.

Problem statement

Write a function group_consecutive(lst) that takes a list lst and returns a new list of lists. Each sublist should contain consecutive elements from lst that are equal to each other. The order of runs should match their order in the original list. If lst is empty, return an empty list. Elements can be of any type and equality should use Python's standard == operator.

Task

Given a list, return a list of sublists where each sublist contains a maximal consecutive run of equal values from the original list.

Examples

Input format

A single argument: a list (possibly empty) of values.

Output format

Return a list of lists, where each inner list is a consecutive run of equal values.

Constraints

Do not use external libraries. Preserve the original element values and relative order. Time complexity should be O(n).

Samples