C优先队列的基本使用方法.doc

C++优先队列的基本使用方法?#includeiostream#includefunctional#includequeueusing namespace std; struct node{????friend bool operator (node n1, node n2)????{????????return n1.priority n2.priority;//为从大到小排列，为从小打到排列????}????int priority;????int value;}; int main(){????const int len = 5;????int i;????int a[len] = {3,5,9,6,2};????//示例1????priority_queueint qi;//普通的优先级队列，按从大到小排序????for(i = 0; i len; i++)????????qi.push(a[i]);????for(i = 0; i len; i++)????{????????coutqi.top() ;????????qi.pop();????}????coutendl; ????//示例2????priority_queueint, vectorint, greaterint qi2;//从小到大的优先级队列，可将greater改为less，即为从大到小????for(i = 0; i len; i++)????????qi2.push(a[i]);????for(i = 0; i len; i++)????{????????coutqi2.top() ;????????qi2.pop();????}????coutendl; ????//示例3????priority_queuenode qn;//必须要重载运算符????node b[len];????b[0].priority = 6; b[0].value = 1;????b[1].priority = 9; b[1].value = 5;????b[2].priority = 2; b[2].value = 3;????b[3].priority = 8; b[3].value = 2;????b[4].priority = 1; b[4].value = 4;?????for(i = 0; i len; i++)????????qn.push(b[i]);????cout优先级\t值endl;????for(i = 0; i len; i++)????{????????coutqn.top().priority\tqn.top().valueendl;????????qn.pop();????}????return 0;} 对于队列里元素为一个结构体类型，按照某一个属性排序，就需要对比较函数进行重载 小结一下： 1、若是定义值类型对象，如：? int??main()?{?? ? ???? priority_queuenode qn; ??? node n1;???? n1.a = 9;???? node n2;???? n2.a = 2;???? node n3;???? n3.a = 50;?? ??? qn.push(n1); ??? qn.push(n2); ??? qn.push(n3); ???? int? size = qn.size(); ???? for ( int? i = 0; i size; i++)???? {???????? cout qn.top().a endl; ? ? ? ? qn.pop();???? }?? ??? ? ?return? 0; }?则定义优先级的时候，直接在类中写个friend 的操作符重载函数即可：? class? node?{?public :????? int? a; ??? node(){}???? node( int? x):a(x){}?friend?? bool? operator( const? node ne1, const? node ne2)//参数也可以为引用，值传递???? {????????? if (ne1.a ne2.a)???????? {????????????? return?? true ;???????? }????????? else???????? {????????????? return?? false ;???????? }???? }?};?其中在c＋＋prim