algorithmic recursion

Definition: A function calls itself directly or indirectly

def func():

    func()

Four elements:

          received parameters

          return value

          Termination conditions

          Recursive disassembly: how to recurse to the next level

Example: Fibonacci Sequence

0，1，1，2，3，5，8 ........

def fibe(n):
    if (n < 2):
        return n
    m = fibe(n - 1) + fibe(n - 2)
    return m

Time complexity: O(N power of 2)

Space complexity: O(N) stack first in last out