优先级队列的实现 和 层次遍历建树

Posted 2020-06-28 棋子

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

class priority_queue
{
private:
    vector<int> data;

public:
    void push(int t){
        data.push_back(t);
        push_heap(data.begin(), data.end());
    }

    void pop(){
        pop_heap(data.begin(), data.end());
        data.pop_back();
    }

    int top() { return data.front(); }
    int size() { return data.size(); }
    bool empty() { return data.empty(); }
};


int main()
{
    priority_queue test;
    test.push(3);
    test.push(5);
    test.push(2);
    test.push(4);

    while (!test.empty()){
        cout << test.top() << endl;
        test.pop();
    }

    return 0;

}

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层次遍历建树 

按层建树是按照给定的数据数组来建立完全二叉树的过程。其中涉及到的基础知识有结构体的创建重命名以及使用、链表的创建和数组遍历。 

#include <stdio.h>
#include <stdlib.h>
#define N 10
#define MAX 100
typedef struct node{
    int data;
    struct node *left;
    struct node *right;
}BTnode;
BTnode *deal(int a[],int n)
{
    int i;
    BTnode *root;
    BTnode *queue[11];
    int front=0,rear=0;//按层，使用队列 
  for(i=0;i<n;i++){
    /*初始化新节点*/ 
  BTnode *t=(BTnode *)malloc(sizeof(BTnode));
  t->left=t->right=NULL;
  t->data=a[i];
   /*入队*/
   queue[++rear]=t; 
  if(i==0){
    root=t;
  }else{
     if(!queue[rear/2]->left){
        queue[rear/2]->left=t;
     }else{
        queue[rear/2]->right=t;
        front++;
     }  
  }
  }
  return root;  
}
/*按层输出二叉树*/
void PrintTree(BTnode *root)
{
     BTnode *t=NULL;
     BTnode *queue[MAX];
     int front=0,rear=0;
     /*入队*/
     queue[++rear]=root;
     /*出队*/
     while(front!=rear){    
     t=queue[++front]; 
     printf("%d",t->data);
     if(t->left) queue[++rear]=t->left;
     if(t->right) queue[++rear]=t->right;
     }
} 
int main(void)
{
    int a
={1,3,5,7,9,2,4,6,8,10};
    BTnode *root=NULL;
    root=deal(a,N);
    PrintTree(root);
    return 0;
}

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