I have three random-access iterators parent, child1, and child2, which point to certain values in a permuted array. (Context: I'm implementing heapsort; those iterators comprise a binary subtree).
I need to determine the iterator, which has the largest referenced value (to maintain the max-heap property of the heap). So, if *parent is the largest, return parent, if *child1 is the largest, return child1, etc.
Pseudocode:
#include <algorithm>
auto iterator = std::max({ parent, child1, child2 });
iterator is now the iterator whose underlying value is the greatest.
The problem is that using this literal pseudocode, std::max would compare the iterators itsself here, not their referenced values. I could do std::max({ *parent, *child1, *child2 }), but it returns decltype(*parent), so how would I get the iterator back from there?
I know it's trivially feasible using some ifs, but isn't there some more elegant way? Does the standard library have something there? I tried several things, but they all seem bulky and inconvenient.
If you don't consider std::max with a custom comparator bulky, here it is:
auto iterator = std::max({ parent, child1, child2 },
[](auto it_a, auto it_b) { return *it_a < *it_b; });