Requirements on types

For the first version, which takes three arguments:

• InputIterator is a model of Input Iterator.

• EqualityComparable is a model of Equality Comparable.

• InputIterator's value type is a model of Equality Comparable.

• An object of InputIterator's value type can be compared for equality with an object of type EqualityComparable.

For the second version, which takes four arguments:

• InputIterator is a model of Input Iterator.

• EqualityComparable is a model of Equality Comparable.

• Size is an integral type that can hold values of InputIterator's distance type.

• InputIterator's value type is a model of Equality Comparable.

• An object of InputIterator's value type can be compared for equality with an object of type EqualityComparable.