错误:无法将'minHeap'从'std :: priority_queue,std :: greater>'转换为'std :: priority_queue

时间:2017-10-03 20:33:36

标签: c++ priority-queue st

我是c ++的初学者。我正在尝试使用std :: priority_queue创建maxheap和minheap。创建一个maxheap工作正常,但不是两个。我似乎无法理解错误。我收到以下错误: 无法将'minHeap'从'std :: priority_queue,比较>'转换为'std :: priority_queue' 尝试搜索互联网但无济于事。以下是代码。

void addNum(int num, priority_queue<int> maxHeap, priority_queue<int> minHeap) {
    if (minHeap.size() == 0 || num > minHeap.top()) 
        minHeap.push(num);
    else if (num < minHeap.top())
        maxHeap.push(num);
}

void createHeaps(vector<int> a) {
    priority_queue<int> maxHeap;
    priority_queue<int, vector<int>, greater<int> > minHeap;
    for (int i = 0; i < a.size(); ++i) {
        int num = a[i];
        addNum(num, maxHeap, minHeap);
    }
}

2 个答案:

答案 0 :(得分:2)

您尝试使用priority_queue<int, vector<int>, greater<int> >类型传递变量,但您的函数需要priority_queue<int>类型。

纠正功能原型:

void addNum(int num, priority_queue<int>& maxHeap, priority_queue<int, vector<int>, greater<int> >& minHeap) {
    if (minHeap.size() == 0 || num > minHeap.top()) 
        minHeap.push(num);
    else if (num < minHeap.top())
        maxHeap.push(num);
}

您必须使用参考。这是因为您需要修改原始集合。

答案 1 :(得分:1)

您的方法也必须使用正确的类型:

void addNum(int num,
            priority_queue<int, >& maxHeap,
            priority_queue<int, std::vector<int>, std::greater<int>>& minHeap) {
    if (minHeap.size() == 0 || num > minHeap.top()) 
        minHeap.push(num);
    else if (num < minHeap.top())
        maxHeap.push(num);
}

或者你可以将你的方法模板化为更通用的

template <typename ... Ts1, typename ... Ts2>
void addNum(int num,
            priority_queue<int, Ts1...>& maxHeap,
            priority_queue<int, Ts2...>& minHeap) {
    if (minHeap.size() == 0 || num > minHeap.top()) 
        minHeap.push(num);
    else if (num < minHeap.top())
        maxHeap.push(num);
}

甚至,简单地说:

template <typename PriorityQueue1, typename PriorityQueue2>
void addNum(int num,
            PriorityQueue1& maxHeap,
            PriorityQueue2& minHeap) {
    if (minHeap.size() == 0 || num > minHeap.top()) 
        minHeap.push(num);
    else if (num < minHeap.top())
        maxHeap.push(num);
}