setpriority_queue等容器如何加入自定义类

Posted 2021-01-04 bloomingflower

以优先队列为例，从cppreference查得，它的模板为

template<

    class T,
    class Container = std::vector<T>,
    class Compare = std::less<typename Container::value_type>

> class priority_queue;

所以我们要定义一个Compare类实现less的功能，在观察less类的内容，https://en.cppreference.com/w/cpp/utility/functional/less

std::less::operator()
bool operator()( const T& lhs, const T& rhs ) const;(until C++14)
constexpr bool operator()( const T& lhs, const T& rhs ) const;(since C++14)
Checks whether lhs is less than rhs.
Parameters
lhs, rhs    -    values to compare
Return value
true if lhs < rhs, false otherwise.

constexpr bool operator()(const T &lhs, const T &rhs) const 
{
    return lhs < rhs;
}

实现非常简单，只要对我们自定义的类实现operator()重载即可