在判断是否符合堆的特性时，我一开始使用的判断语句是：
if ((heap[root] > heap[2 * root] || heap[root] > heap[2 * root + 1]) && (heap[2 * root]!= -999999 && heap[2 * root + 1]!= -999999)) flag_min = 0;//不是小根堆；虽然我将每个空节点都设置为了-999999.但是这样有一个致命的错误，就是root*2可能超过设置的数组长度。导致错误。 后来改为了：
if (2 * root <= N && heap[root] > heap[2 * root]) flag_min = 0; if (2 * root + 1 <= N && heap[root] > heap[2 * root + 1]) flag_min = 0;这样可以直接防止数据越界。
#include<bits/stdc++.h> using namespace std; vector<int> heap(1009),ans; int flag_min, flag_max; int M, N; void preTraversal(int root) { if (root > N) return; preTraversal(root * 2); preTraversal(root * 2 + 1); ans.push_back(heap[root]); } void judge_maxheap(int root) { if (root > N) return; //出错的地方 //----------------------------------------------------------------------// if (2 * root <= N && heap[root] < heap[2 * root]) flag_max = 0; if (2 * root + 1 <= N && heap[root] < heap[2 * root + 1]) flag_max = 0; //----------------------------------------------------------------------// judge_maxheap(root * 2); judge_maxheap(root * 2 + 1); } void judge_minheap(int root) { if (root > N) return; //----------------------------------------------------------------------// if (2 * root <= N && heap[root] > heap[2 * root]) flag_min = 0; if (2 * root + 1 <= N && heap[root] > heap[2 * root + 1]) flag_min = 0; //----------------------------------------------------------------------// judge_minheap(root * 2); judge_minheap(root * 2 + 1); } int judge() { if (heap[1] > heap[2]) {//当大根堆判断 flag_min = 0; judge_maxheap(1); if(flag_max == 1) return 1; } else if (heap[1] < heap[2]) {//当小根堆判断 flag_max = 0; judge_minheap(1); if(flag_min == 1) return 1; } else { judge_minheap(1); judge_maxheap(1); if (flag_max + flag_min == 1) return 1; } return 0; } int main() { #ifdef ONLINE_JUDGE #else freopen("Text.txt", "r", stdin); #endif // ONLINE_JUDGE cin >> M >> N; for (int j = 0; j < M; j++) { flag_min = 1; flag_max = 1; fill(heap.begin(), heap.end(), -999999); for (int i = 1; i <= N; i++) { cin >> heap[i]; } if (judge() == 1) { if (flag_max == 1) cout << "Max Heap" << endl; else cout << "Min Heap" << endl; } else { cout << "Not Heap" << endl; } preTraversal(1); cout << ans[0]; for (int i = 1; i < N; i++) cout << " " << ans[i]; cout << endl; ans.clear(); } }