05-树6. Path in a Heap

最新推荐文章于 2024-08-27 22:55:12 发布

穆晨

最新推荐文章于 2024-08-27 22:55:12 发布

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分类专栏：数据结构文章标签： c pat 二叉堆

本文链接：https://blog.youkuaiyun.com/qq_22902423/article/details/45402793

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本文介绍了一道关于二叉堆的编程题，主要内容包括如何将一系列整数插入到初始为空的最小堆中，并针对指定索引打印从该位置元素到堆顶的路径。文章提供了完整的代码实现，并附带了一个示例输入输出，展示了如何构建二叉堆及查询路径。

Insert a sequence of given numbers into an initially empty min-heap H. Then for any given index i, you are supposed to print the path from H[i] to the root.

Input Specification:

Each input file contains one test case. For each case, the first line gives two positive integers N and M (<=1000) which are the size of the input sequence, and the number of indices to be checked, respectively. Given in the next line are the N integers in [-10000, 10000] which are supposed to be inserted into an initially empty min-heap. Finally in the last line, M indices are given.

Output Specification:

For each index i in the input, print in one line the numbers visited along the path from H[i] to the root of the heap. The numbers are separated by a space, and there must be no extra space at the end of the line.
Sample Input:5 3
46 23 26 24 10
5 4 3

Sample Output:24 23 10
46 23 10
26 10

这题属于二叉堆的练手题，开始以为二叉堆很难。。结果发现还是比AVL和CBT容易一些。coding不到半小时就AC了。。好久没有这么痛快了。

#include<stdio.h>

int IsFull(int n,int i);
void Insert(int* p,int k,int i);

int main(){
    int m,n,i,k;
    scanf("%d%d",&m,&n);
    int heap[m+1];
    heap[0] = -20000;
//  构建heap 
    for(i = 1;i<=m;i++){
        scanf("%d",&k);
        if(1 == i)
            heap[i] = k;
        else{
            if(IsFull(m,i-1))
                break;
            else
                Insert(heap,k,i);       
        }
    }
//  读取，输出
    for(i = 0;i<n;i++){
        scanf("%d",&k);
        for(int j = k;j;j/=2){
            if(j == k)
                printf("%d",heap[j]);
            else
                printf(" %d",heap[j]);
        }
        if(i!=n-1)
            printf("\n");
    } 

    return 0;
} 

void Insert(int* p,int k,int i){
    for(;p[i/2]>k;i/=2)
        p[i] = p[i/2];
    p[i] = k;
}

int IsFull(int n,int i){
    if(n == i)
        return 1;
    return 0;
}