Convert State Stream to Events

You are given an array `states` where `states[i]` is the categorical output of a monitoring function at timestamp `i`. Consecutive equal values belong to the same event. Write a function that converts this stream into a list of events of the form `(value, start_index, end_index)`, where `start_index` and `end_index` are inclusive. Example: - Input: `['A', 'A', 'B', 'B', 'B', 'A']` - Output: `[('A', 0, 1), ('B', 2, 4), ('A', 5, 5)]` Follow-up: given an integer `k`, only runs with length at least `k` should be considered valid events. Any consecutive run shorter than `k` should be excluded from the output. Implement the function and analyze its time and space complexity.