c_cpp 数组是否代表堆

Posted 2021-05-14

//https://www.geeksforgeeks.org/how-to-check-if-a-given-array-represents-a-binary-heap/
#include <iostream>
using namespace std;

bool isHeap (int a[],int i, int n) {
    int l= 2*i+1, r= 2*i+2;
    if (l<n && r<n) {
        if (a[i] > a[l] && a[i] > a[r] && isHeap(a, l, n) && isHeap (a, r,n))
            return 1;
        else
            return 0;
    }
    else if (l<n) {
        if (a[i] > a[l] && isHeap(a, l, n))
            return 1 ;
        else
            return 0;
    }
    return 1;
}

int main() {
    int t;
    cin>>t;
    while (t-->0) {
        int n;
        cin>>n;
        int a[n];
        for (int i=0;i<n;i++)
            cin>> a[i];

        cout<< isHeap(a,0, n) << "\n";
    }
}