I received an online coding challenge, and after about a week, I was told I was rejected.

I didn't manage to pass the coding challenge, mainly due to time limitations.

The question provided an array a which contained a permutation of the first n natural numbers, along with a number k. You have a series of plants, and initially, all plants are not in bloom. At the i-th iteration, the plant at the location specified by the value i in the array was going to bloom. Once a plant bloomed, it stayed bloomed forever. We define a group as the number of adjacent bloomed plants. Find the last iteration that had a group of size k.

E.g., Given a = [1, 3, 2, 4]:

Initial plants: 0 0 0 0

Iteration 1: 1 0 0 0 (1 group of size 1)

Iteration 2: 1 0 1 0 (2 groups of size 1)

Iteration 3: 1 1 1 0 (1 group of size 3)

Iteration 4: 1 1 1 1 (1 group of size 4)