C++ 之优先队列

bool myCmp(int a, int b) {
    // 比较a和b的个位数
    return a % 10 < b % 10;
}

int main() {
    srand(time(NULL));

    // 默认情况下，最大堆
    priority_queue<int> pq;
    for (int i = 0; i < 10; ++i) {
        int num = rand() % 100;
        pq.push(num);
        cout << "insert " << num << " in priority queue." << endl;
    }
    while (!pq.empty()) {
        cout << pq.top() << " ";
        pq.pop();
    }
    cout << endl << endl;

    // 底层最小堆
    priority_queue<int, vector<int>, greater<int>> pq2;
    for (int i = 0; i < 10; ++i) {
        int num = rand() % 100;
        pq2.push(num);
        cout << "insert " << num << " in priority queue." << endl;
    }
    while (!pq2.empty()) {
        cout << pq2.top() << " ";
        pq2.pop();
    }

    cout << endl << endl;

    // 使用自定义Comparator的priority queue
    priority_queue<int, vector<int>, function<bool(int, int)>> pq3(myCmp);
    for (int i = 0; i < 10; ++i) {
        int num = rand() % 100;
        pq3.push(num);
        cout << "insert " << num << " in priority queue." << endl;
    }
    while (!pq3.empty()) {
        cout << pq3.top() << " ";
        pq3.pop();
    }
    return 0;
}