template<class RanIt>
void make_heap(RanIt first, RanIt last);
template<class RanIt, class Pred>
void make_heap(RanIt first, RanIt last, Pred pr);
The first template function reorders the sequence designated by iterators in the range [first, last) to form a heap
ordered by operator<.
The function evaluates the ordering predicate X < Y at most 3 * (last - first) times.
The second template function behaves the same, except that it replaces operator<(X, Y) with pr(X, Y).
Sample programs: heap and heap (predicate version).