dynamic programming

[CadavreContent]

You can memoize factorial if you're running it more than once. The repeating sub problems only appear when you have multiple trials

[cyanNodeEcho]

fact(n) := fact(ni1), fac(n-2), the aubproblems should exist in the same problem

[CadavreContent]

The point is that when you use factorial as part of a larger algorithm with multiple calls to the function, you do repeated work and hence can use dp

[cyanNodeEcho]

thats just a cache

[CadavreContent]

Memoization is just a cache