priority_queue

使用priority_queue，并且重载运算符就可以。但是要注意优先队列是大根堆。和sort是相反的。

#include<iostream>
#include<math.h>
#include<queue>
using namespace std;
struct complex
{
    int a;int b;
    inline bool operator < (const complex &c)const{
        if((a*a+b*b)==(c.a*c.a+c.b*c.b)){
            return c.b>b;
        }return (a*a+b*b)<(c.a*c.a+c.b*c.b);
    }    
}; 
int main()
{
    int n;
    string s;
    while(cin>>n){
        getchar();
        priority_queue<complex> q;
        complex c;
        for(int i=0;i<n;i++){
            getline(cin,s);
            //cout<<s<<endl;
            if(s[0]=='P'){
                if(q.empty())
                    printf("empty\n");
                else{
                    c=q.top();q.pop();
                    printf("%d+i%d\n",c.a,c.b);
                    printf("SIZE = %d\n",q.size());
                }
            }else if(s[0]=='I'){
                int pos=s.find(" ")+1;
                int num=0;
                while(s[pos]>='0'&&s[pos]<='9'){
                    num=num*10+s[pos]-'0';
                    pos++;
                }
                c.a=num;
                pos+=2;
                num=0;
                while(s[pos]>='0'&&s[pos]<='9'){
                    num=num*10+s[pos]-'0';
                    pos++;
                }
                c.b=num;
                q.push(c);
                printf("SIZE = %d\n",q.size());
            }
        }
    }
    return 0;    
}