def find_pos(arr):
    pos = None
    for i in range(len(arr) - 1):
        if arr[i] > arr[i + 1]:
            pos = i
    return pos


def find_max_lower_idx(pos):
    max_lower = 0
    for idx in range(pos + 1, len(arr)):
        if max_lower < arr[idx] < arr[pos]:
            max_lower = idx
    return max_lower


def swap(pos_1, pos_2, arr):
    x = arr[pos_1]
    arr[pos_1] = arr[pos_2]
    arr[pos_2] = x


def get_previous_permutation(arr):
    pos = find_pos(arr)
    if pos is None:
        return sorted(arr, reverse=True)
    max_lower = find_max_lower_idx(pos)
    swap(pos, max_lower, arr)
    return arr[:pos + 1] + sorted(arr[pos + 1:], reverse=True)



if __name__ == '__main__':
    arr = [1, 3, 2, 5, 4]
    print(f'Got - {arr}')
    print(f'Previous permutation - {get_previous_permutation(arr)}')