While trying to understand the difference between Theta and O notation I came across the following statement :

The Theta-notation asymptotically bounds a function from above and below. When
we have only an asymptotic upper bound, we use O-notation.

But I do not understand this. The book explains it mathematically, but it's too complex and gets really boring to read when I am really not understanding.

Can anyone explain the difference between the two using simple, yet powerful examples.

algorithm big-o
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