Suppose I have a std::vector A$.$ This vector has only values in the range of $0$

to A$.$size$(),$ inclusive. For example, if there are $5$ values in A$,$ then the only values it can

have are $\{0,1,2,3,4,5\},$ although not necessarily in that order. Duplicate values might be

present too.

Obviously, at least one value is missing. Using O$($n$)$ worst$-$case time and O$($n$)$ space, where

n is A$.$size$(),$ determine which value$($s$)$ are missing from the vector. You may not use any

standard library data structure other than std::vector. For full credit, you should not use

any more space than is strictly necessary to solve this problem, other than basic overhead

$($a std::vector is still preferred to a C$-$style array and won$$t be penalized, even though it

does take some additional space, for example$).$ Justify the running time and space of your

approach.

$3.$ Repeat the previous problem, but with the added information that now, A has no duplicates.

Can you find the missing element in O$($n$)$ time with O$(1)$ space