Memory Limit Exceeded

A dead cycle leads to

It is not necessarily because you have created too many variables explicitly , For example, create too many lists , Dictionaries, etc .
It could be a dead cycle , Writing the loop by yourself does not make the key variables of the loop exit change during the loop process ,
The cycle is running , Memory keeps increasing , Cause the memory limit to be exceeded .
For example, let's find the factor of a certain number , Initialization factor fac by 1,
Each cycle ,fac It should increase by itself 1, And mirror pairs ,
An error will be reported that the memory is out of limit ,
It didn't report TLE, So it's hard to find .

def get_fac(self, target):
        if target == 1:
            return []
        fac = 1
        facs = []

        while fac*fac <= target:
            if target % fac == 0: # in O(N)
                facs.append(fac) # list index O(N)
                if fac != 1 and fac*fac != target:
                    facs.append(target//fac)
            # fac += 1 #  I forgot to write here 
        return facs

Lists lead to

Maybe the list takes up a lot of memory , Just change to a dictionary , This applies only to situations that can be replaced by dictionaries .