max_heapify procedure on heap

Question

i have these procedure

#include 
using namespace std;

int parent(int i ){
    return  i/2;
}

int left(int i ){
    return  2*i;
}

int right(i         


        

Answer 1

You translated the pseudo-code from the Wikipedia article into C++ code, but you accidentally altered the logic. In the Wikipedia article, you'll notice that the recursion only happens conditionally: that is, if largest ≠ i

if largest ≠ i then:
    swap A[i] ↔ A[largest]
    Max-Heapify(A, largest)

Translated into C++, this should read something like:

if (largest != i) {
  swap(a[i], a[largest]);
  Max_Heapify(largest);
}

Again, notice that the recursive call to Max_Heapify only happens conditionally, when largest != i. In your code, you recursively call Max_Heapify unconditionally, meaning that you keep recursing no matter what. So obviously your program is going to crash with a stack overflow. Unlike iteration, you can't recurse infinitely because you quickly run out of stack space.