If you want to modify an element in a priority queue, you would need
to remove the element, modify it, and then insert it back into the
priority queue. However, this can be inefficient for large priority
queues since removing and inserting elements can be expensive
operations.
In C++, the standard priority queue container does not provide a
direct way to modify elements. Instead, you would need to implement a
custom priority queue data structure that allows
efficient modification of elements.
One way to do this is to use a combination of a heap-based
priority queue and a hash table (or a map) that maps elements
to their positions in the heap. The hash table allows fast lookup of an
element's position in the heap, and the heap-based priority queue allows
efficient access to the highest-priority element.
Here is a simple example of a custom priority queue data structure
that supports efficient modification of elements: