Debug.Log affect the code?

I just learned something about unity.
I love it very much, but I had a problem when I used it.
I compiled a maze, (the picture 1)
but I am confused about the code in the program(the picture 3)
If I don’t delete, it will be the picture 1,
If I delete this code, the maze will be just like picture 2. It’s not what I want.
I tried to build and run, but the result of the operation is just like the picture 2

It is so queer. 

Software Development Environment:
mac 10.10.5 (14F1713)
unity  5.3.6f1 Personal


The most likely way that using Debug.Log can affect code output is if you have some timing issues (normally involving multithreading) where the delay caused by logging to screen/file alters the order in which two functions return their output.

update I just noticed you’re using the System.Random class, but you’re not specifying an initial seed, so you’ll be using Environment.tickCount as the seed. Since Debug.Log takes more ticks, you’re getting a different seed.

We don’t know your maze generation code - are you using threads?