04-树9. Path in a Heap (25)

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本文介绍如何构建一个最小堆并实现从指定节点到根节点的路径查找功能。输入包括序列大小、待检查的索引数量及数值序列，输出则是从指定索引开始到根节点的路径。

04-树9. Path in a Heap (25)

时间限制

150 ms

内存限制

65536 kB

代码长度限制

8000 B

判题程序

Standard

作者

CHEN, Yue

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

#include <stdio.h>
void insert(int *heap, int val) {
	int child = ++heap[0];
	int parent = child / 2;
	while (parent > 0 && heap[parent] > val) {			//上滤
		heap[child] = heap[parent];
		child = parent;
		parent = child / 2;
	}
	heap[child] = val;
}
int main() {
//	freopen("test.txt", "r", stdin);
	int n, m;
	scanf("%d%d", &n, &m);
	int heap[1000] = {};				//0位置放置堆中元素大小，1位置为堆顶
	for (int i = 0; i < n; ++i) {
		int num;
		scanf("%d", &num);
		insert(heap, num);
	}
	while (m--) {
		int index;
		scanf("%d", &index);
		while (index > 0) {
			printf("%d", heap[index]);
			if (index != 1)
				printf(" ");
			index /= 2;
		}
		printf("\n");
	}
	return 0;
}

题目链接：http://www.patest.cn/contests/mooc-ds/04-%E6%A0%919