c-优先级队列的元素顺序为何不是长尾词？

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我正在编写一个用于计算字符串中字符出现频率的程序。这是我的计划的开始：

cppusing namespace std;

// Counting methodsint* CountCharOccurence(string text){ int* charOccurrence=new int[127]; for(int i=0; i 我正在编写霍夫曼编码.这是我的计划的开始：

using namespace std; //Counting methods int *CountCharOccurence(string text) { int *charOccurrence = new int[127]; for(int i = 0; i < text.length(); i++) { charOccurrence[text[i]]++; } return charOccurrence; } void DisplayCharOccurence(int *charOccurrence) { for(int i = 0; i < 127; i++) { if(charOccurrence[i] > 0) { cout << (char)i << ": " << charOccurrence[i] << endl; } } } //Node struct struct Node { public: char character; int occurrence; Node(char c, int occ) { character = c; occurrence = occ; } bool operator < (const Node* node) { return (occurrence < node->occurrence); } }; void CreateHuffmanTree(int *charOccurrence) { priority_queue<Node*, vector<Node*> > pq; for(int i = 0; i < 127; i++) { if(charOccurrence[i]) { Node* node = new Node((char)i, charOccurrence[i]); pq.push(node); } } //Test while(!pq.empty()) { cout << "peek: " << pq.top()->character << pq.top()->occurrence << endl; pq.pop(); } } int main(int argc, char** argv) { int *occurrenceArray; occurrenceArray = CountCharOccurence("SUSIE SAYS IT IS EASY"); DisplayCharOccurence(occurrenceArray); CreateHuffmanTree(occurrenceArray); return (EXIT_SUCCESS); }

程序首先输出带有出现次数的字符.看起来很好：

: 4 A: 2 E: 2 I: 3 S: 6 T: 1 U: 1 Y: 2

但是必须以优先级顺序显示节点内容的测试循环输出：

peek: Y2 peek: U1 peek: S6 peek: T1 peek: I3 peek: E2 peek: 4 peek: A2

这不是预期的顺序.为什么？

优先级队列中的元素是指针.由于您没有提供带有2个指向Node对象的函数,因此默认比较函数会比较2个指针.

bool compareNodes(Node* val1, Node* val2) { return val1->occurence < val2->occurence; } priority_queue<Node*, vector<Node*>,compareNodes > pq;

您的操作符< Node与Node *比较时使用