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) time and O (n) space, where n is A. size (), determine which value (s) are missing from the vector.
