[英]priority_queue operator < implementation trouble
I have multiple events of different types that I need to push into a priority queue and make sure they are sorted by the event time. 我有多个不同类型的事件,需要推入优先级队列,并确保它们按事件时间排序。
struct Event {
double event_time;
int type;
};
I use a class EventCompare like so: 我使用如下类的EventCompare:
class EventCompare {
public:
bool operator()(Event &a, Event &b) {
return a.event_time > b.event_time;
}
};
and initialize the priority queue: 并初始化优先级队列:
priority_queue<Event, vector<Event>, EventCompare> event_scheduler;
When I push Events into the priority queue, they are still not sorted. 当我将事件推送到优先级队列中时,它们仍未排序。 Is there something wrong with my implementation? 我的实现有问题吗?
I generate my Events in such a way: 我以以下方式生成事件:
srand((unsigned int)time(NULL));
while(action_time < 100) {
u = (double)rand()/(double)RAND_MAX;
action_time += -log(u)/25;
Event e = {action_time, 0};
event_scheduler.push(e);
}
I then do another similar loop but resetting the rand seed, setting action_time back to 0, and for an event with type 1, the event with type 1 does not get placed in order of event_time. 然后,我执行另一个类似的循环,但是重置rand种子,将action_time设置回0,对于类型1的事件,类型1的事件不会按event_time的顺序放置。
If you're intending for the oldest events (event_time lowest) to be at top of the queue, you need to reverse your custom compare. 如果您打算将最早的事件(最低的event_time)放在队列的顶部,则需要反转自定义比较。 By default std::priority_queue puts the greatest at the top: 默认情况下,std :: priority_queue将最大的放在顶部:
class EventCompare {
public:
bool operator()(Event &a, Event &b) {
return a.event_time > b.event_time;
}
};
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