How can I implement a priority queue in C++ using custom types?

How can I implement a priority queue in C++ using custom types?

You can implement a priority queue in C++ by using the STL's priority_queue and defining a custom comparator for your types.

Can you show me an example of a custom type and the comparator?

Sure! Let's say you have a Task struct with a priority. You can define a comparator like this:

struct Task {
    std::string name;
    int priority;
};

struct CompareTask {
    bool operator()(const Task& t1, const Task& t2) {
        return t1.priority < t2.priority;
    }
};

This will allow you to prioritize tasks based on their priority value.

How do I use this comparator with the priority queue?

You can use the comparator when declaring your priority queue like this:

std::priority_queue<Task, std::vector<Task>, CompareTask> taskQueue;

Now, when you push tasks into taskQueue, they will be ordered by priority.

What if I want to change the priority of a task?

You would typically need to remove the task, change its priority, and then reinsert it into the priority queue, as the STL priority queue does not support direct modification.