PATA1017 Queueing at Bank

用priority_queue的一個典型例題，記錄一下。

#include<iostream> 
#include<map>
#include<algorithm>
#include<vector>
#include<stack>
#include<queue>
#include<math.h>
using namespace std;

struct people{
	int arrive;
	int start;
	int process;
	
	bool operator<(const people& p) const{
		return arrive>p.arrive;
	}
};

struct cmp1{
	bool operator() (people a,people b){
		return (a.start+a.process)>(b.start+b.process);
	}
};

priority_queue<people,vector<people>,cmp1> bank;
priority_queue<people> wait;

int parseStr(string str){
	int h=stoi(str.substr(0,2));
	//cout<<"h:"<<h<<endl;
	int m=stoi(str.substr(3,2));
	//cout<<"m:"<<m<<endl;
	int s=stoi(str.substr(6,2));
	//cout<<"s:"<<s<<endl;
	//cout<<"parse:"<<h*60*60+m*60+s<<endl;
	return h*60*60+m*60+s;
}

int main(){
	
	int num;
	int bcnt;
	cin>>num>>bcnt;
	
	int realnum=num;
	for(int i=0;i<num;i++){
		string arrive;
		int process;
		cin>>arrive>>process;
		if(arrive<="17:00:00"){
			int arr=parseStr(arrive);
			people* p=new people();
			p->arrive=arr;
			p->process=process*60;
			wait.push(*p);
			//cout<<"$$$:"<<wait.top().arrive<<endl;
		}else{
			realnum--;
		}
	}
	
	int curtime=8*3600;
	int totalwait=0;
	int curcnt=0;
	//cout<<curtime<<endl;
	while(!wait.empty()){
		//cout<<"!!!:"<<curtime<<endl;
		if(!bank.empty()){
			people btop=bank.top();
			people wtop=wait.top();
			if((btop.start+btop.process)<wtop.arrive){
				bank.pop();
				curtime=btop.start+btop.process;
				totalwait+=btop.start-btop.arrive;
				curcnt--;
			}else if(curcnt<bcnt){
				wait.pop();
				curtime=max(curtime,wtop.arrive);
				wtop.start=curtime;
				bank.push(wtop);
				curcnt++;
			}else{
				bank.pop();
				curtime=btop.start+btop.process;
				totalwait+=btop.start-btop.arrive;
				wait.pop();
				wtop.start=curtime;
				bank.push(wtop);
			}
		}else{
			people wtop=wait.top();
			wait.pop();
			curtime=max(curtime,wtop.arrive);
			//cout<<"???:"<<curtime<<endl;
			wtop.start=curtime;
			bank.push(wtop);
			curcnt++;
		}
		//cout<<curtime<<endl;
	}
	
	while(!bank.empty()){
		people out=bank.top();
		bank.pop();
		totalwait+=out.start-out.arrive;
	}
	//cout<<totalwait<<endl;
	double res=((double)totalwait)/60/realnum;
	
	printf("%.1f",res);
	
	return 0;
	
}