C++priority_queue⽤法（⼤顶堆，⼩顶堆）
template <class T, class Container = vector<T>,
class Compare = less<typename Container::value_type> > class priority_queue;
例⼦
#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <map>
#include <unordered_map>
#include <string>
#include <queue>
司马昭之心歇后语using namespace std;
/**
默认⽐较函数为less, ⼤顶堆
**/
void defaultCmpLess() {
cout << "=========defaultCmpLess(big heap)========" << endl;
priority_queue<int> q;
for (int i = 0; i < 10; i++) {
q.push(rand()%20);
}
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while (!q.empty()) {
cout << q.top() << " ";
q.pop();
}
cout <<endl;
}
/**
使⽤greater⽐较函数，⼩顶堆
**/
void uCmpGreater() {
cout << "=========uCmpGreater(small heap)========" << endl; priority_queue<int, vector<int>, greater<int> > q;
for (int i = 0; i < 10; i++) {
q.push(rand()%20);
}
while (!q.empty()) {
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cout << q.top() << " ";
q.pop();
}
cout <<endl;
}
//==========================
struct Node
{
int x, y;
Node(int a = 0, int b = 0):x(a), y(b){};
friend bool operator<(const Node &a, const Node &b);
};
inline bool operator<(const Node &a, const Node &b) {
if (a.x != b.x)
return a.x < b.x;
return a.y > b.y;
}
/**
运算符重载
**/
void overloadOperator() {
cout << "=========overload Operator< =========" << endl;
cout << "a.x < b.x; a.y > b.y" << endl;
priority_queue<Node> q;
for (int i = 0; i < 10; i++) {
q.push( Node( rand()%20, rand()%20 ) );
}
while (!q.empty()) {
cout << q.top().x << "," << q.top().y << endl;
q.pop();
}
cout << endl;
}
//=========================
/**
⾃构建⽐较函数
**/
struct cmp2
{
bool operator()(int a, int b) {
领带打法图解return a < b;
}
};
void designCmp() {
cout << "=========designCmp========" << endl;
cout << "operator a<b" << endl;
priority_queue<int, vector<int>, cmp2 > q;
for (int i = 0; i < 10; i++) {
q.push(rand()%20);
}
while (!q.empty()) {
cout << q.top() << " ";
q.pop();
}
cout <<endl;
}
int main(int argc, char const *argv[])
{
defaultCmpLess();
诗歌评论uCmpGreater();
八月十五overloadOperator();
designCmp();
}
/**
=========defaultCmpLess(big heap)======== 18 18 13 12 10 9 9 7 4 3
=========uCmpGreater(small heap)======== 0 0 2 3 5 7 7 9 12 12
=========overload Operator< =========
a.x <肾都有什么病
我的老师300字优秀作文b.x; a.y > b.y
19,1
19,9
19,18
17,6
16,15
12,7
10,13
9,17
3,9
0,13
=========designCmp========
operator a<b
17 16 14 13 12 11 8 7 5 5
**/
