https://pintia.cn/problem-sets/994805342720868352/problems/1071785408849047552
In computer science, a heap is a specialized tree-based data structure that satisfies the heap property: if P is a parent node of C, then the key (the value) of P is either greater than or equal to (in a max heap) or less than or equal to (in a min heap) the key of C. A common implementation of a heap is the binary heap, in which the tree is a complete binary tree. (Quoted from Wikipedia at https://en.wikipedia.org/wiki/Heap_(data_structure))
One thing for sure is that all the keys along any path from the root to a leaf in a max/min heap must be in non-increasing/non-decreasing order.
Your job is to check every path in a given complete binary tree, in order to tell if it is a heap or not.
Input Specification:
Each input file contains one test case. For each case, the first line gives a positive integer N (1<N≤1,000), the number of keys in the tree. Then the next line contains N distinct integer keys (all in the range of int), which gives the level order traversal sequence of a complete binary tree.
Output Specification:
For each given tree, first print all the paths from the root to the leaves. Each path occupies a line, with all the numbers separated by a space, and no extra space at the beginning or the end of the line. The paths must be printed in the following order: for each node in the tree, all the paths in its right subtree must be printed before those in its left subtree.
Finally print in a line Max Heap if it is a max heap, or Min Heap for a min heap, or Not Heap if it is not a heap at all.
Sample Input 1:
8
98 72 86 60 65 12 23 50
Sample Output 1:
98 86 23
98 86 12
98 72 65
98 72 60 50
Max Heap
Sample Input 2:
8
8 38 25 58 52 82 70 60
Sample Output 2:
8 25 70
8 25 82
8 38 52
8 38 58 60
Min Heap
Sample Input 3:
8
10 28 15 12 34 9 8 56
Sample Output 3:
10 15 8
10 15 9
10 28 34
10 28 12 56
Not Heap
代码：
#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 10;
int N;
int a[maxn];
vector<int> v;
void dfs(int st) {
if(st * 2 > N && st * 2 + 1 > N) {
if(st <= N) {
for(int i = 0; i < v.size(); i ++) {
printf("%d", v[i]);
printf("%s", i != v.size() - 1 ? " " : "\n");
}
}
} else {
v.push_back(a[st * 2 + 1]);
dfs(st * 2 + 1);
v.pop_back();
v.push_back(a[st * 2]);
dfs(st * 2);
v.pop_back();
}
}
int main() {
scanf("%d", &N);
for(int i = 1; i <= N; i ++)
scanf("%d", &a[i]);
v.push_back(a[1]);
dfs(1);
int MaxHeap = 1, MinHeap = 1;
for(int i = 2; i <= N; i ++) {
if(a[i / 2] > a[i]) MinHeap = 0;
if(a[i / 2] < a[i]) MaxHeap = 0;
}
if(MaxHeap == 1)
printf("Max Heap\n");
else if(MinHeap == 1)
printf("Min Heap\n");
else printf("Not Heap\n");
return 0;
}
dfs 搜索路径 然后根据最大堆最小堆的性质判断 刚刚好上午写好了堆排序(FH 的堆排序)
FHFHFH 33 天倒计时
原文地址：https://www.cnblogs.com/zlrrrr/p/10329252.html