Cons lst = null; for (int i = 0; i < n; i++ ) lst = cons( i, lst ); lst = nreverse(lst);

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What is the Big O of this code?
**

**Answer: B**

The `cons` is always *O(1)*, inside a loop of *n*,
so the loop is *O(n)*. `nreverse` is also *O(n)*.
*O(n) + O(n) = O(n)*.

**Rule: If the order in which you cons up a list
makes it come out backwards, nreverse it at the end.**