def get_cycles(a):
    n = len(a)
    used = [0] * n
    cycles = []
    for i in range(n):
        if not used[i]:
            nw = []
            nxt = i
            while not used[nxt]:
                nw.append(a[nxt])
                used[nxt] = 1
                nxt = a[nxt] - 1
            if nw:
                cycles.append(nw)
    return cycles

def rev(a):
    n = len(a)
    nw = [0] * n
    for i in range(n):
        nw[a[i] - 1] = i + 1
    return nw

a = [4, 7, 3, 1, 6, 5, 8, 2]
b = [4, 6, 3, 2, 8, 7, 1, 5]
c = [7, 8, 2, 3, 6, 5, 4, 1]
print(get_cycles(a))

print(rev(b))
print(get_cycles(rev(b)))

print(get_cycles(c))