题目地址

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))

Your job is to tell if a given complete binary tree is a heap.

Input Specification:
Each input file contains one test case. For each case, the first line gives two positive integers: M (≤ 100), the number of trees to be tested; and N (1 < N ≤ 1,000), the number of keys in each tree, respectively. Then M lines follow, each 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, 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. Then in the next line print the tree's postorder traversal sequence. All the numbers are separated by a space, and there must no extra space at the beginning or the end of the line.

Sample Input:
3 8
98 72 86 60 65 12 23 50
8 38 25 58 52 82 70 60
10 28 15 12 34 9 8 56

Sample Output:
Max Heap
50 60 65 72 12 23 86 98
Min Heap
60 58 52 38 82 70 25 8
Not Heap
56 12 34 28 9 8 15 10

#include <cstdio>
#include <cstring>
#include<iostream>
#include <vector>
#include<math.h>
#include<string>
#include<queue>
#include <algorithm>            
#include<set>
#include<map>
using namespace std;
const int maxn=100010,inf=1000000000;bool is_max,is_min;int a[maxn];
int m,n;
void dfs1(int i){
    if(i>n) return;
    if(2*i<=n&&a[2*i]>a[i]) is_max=0;
    if(2*i+1<=n&&a[2*i+1]>a[i]) is_max=0;
    dfs1(2*i);
    dfs1(2*i+1);
}
void dfs2(int i){
    if(i>n) return;
    if(2*i<=n&&a[2*i]<a[i]) is_min=0;if(2*i+1<=n&&a[2*i+1]<a[i]) is_min=0;
    dfs2(2*i);
    dfs2(2*i+1);
}
int cnt=0;
void pos(int i){
    if(i>n) return;
    pos(2*i);
    pos(2*i+1);
    if(cnt!=0) cout<<" ";
    cout<<a[i];cnt++;
}
int main(){
    cin>>m>>n;
    while(m--){
        for(int i=1;i<=n;i++) cin>>a[i];
        if(a[1]>a[n]) {           //大顶堆；
            is_max=1;is_min=0;
            dfs1(1);
        }
        else {
            is_min=1;is_max=0;
            dfs2(1);
        }
        if(is_max) cout<<"Max Heap";
        else if(is_min) cout<<"Min Heap";
        else cout<<"Not Heap";
        cout<<endl;
        cnt=0;pos(1);
        cout<<endl;
    }
    return 0;
}