py function recursion

1. There used to be a mountain, a temple in the mountains, an old monk in the temple telling a story ...

2. Recursion: The program calls itself.

3. Form: The function definition has a direct or indirect call to itself.

For example: factorial: n!= 1 x 2 x 3 x ... x n;

Consider P (n) = n * (n-1) from backs ago!, p (n-1) = (n-1) * (n-2)!

4. Initial conditions, recursive parts. Qiatouquwei stay in the middle

5. The If problem is simple enough:

Direct Problem Solving

Return solution

Else

One or more smaller issues that are isomorphic to the original problem

Solve these smaller problems one by one

Combine the results to get the final Solution

Return solution

6. Fibonacci Series: 1, 1, 2, 3

py function recursion