cycle_notation.py

test_case = [3, 5, 2, 4, 7, 8, 1, 6]
expected_result = [[1, 3, 2, 5, 7], [4], [6, 8]]


def first_idx_unseen(seen_array):
    for i in range(len(seen_array)):
        if seen_array[i] == False:
            return i


def order_cycle(cycle):
    min_value_idx = cycle.index(min(cycle))
    return cycle[min_value_idx:] + cycle[:min_value_idx]


def cycle_notation(permutation):
    result = []
    cycle = []
    idx = 0
    idx_to_check = len(permutation)
    seen = [False] * len(permutation)

    while idx_to_check > 0:
        while (seen[idx] == False):
            cycle.append(permutation[idx])
            seen[idx] = True
            idx = permutation[idx] - 1
            idx_to_check -= 1
        result.append(order_cycle(cycle))
        cycle = []
        idx = first_idx_unseen(seen)
    return result