heapsort be sorting now

heapsort.c

@@ -2,17 +2,15 @@
 #include <stdlib.h>
 
 void Heapify(int A[], int i, int heapsize) {
-  int left = 2 * i +1;
-  int right = (2 * i) + 2;
+  int left = 2 * i;
+  int right = 2 * i + 1;
   int largest = i;
 
-  if (left <= heapsize && A[left] > A[largest]) {
+  if (left < heapsize && A[left] > A[largest]) {
     largest = left;
-  } else {
-    largest = i;
   }
 
-  if (right <= heapsize && A[right] > A[largest]) {
+  if (right < heapsize && A[right] > A[largest]) {
     largest = right;
   }
 
@@ -24,6 +22,22 @@ void Heapify(int A[], int i, int heapsize) {
   }
 }
 
+void BuildHeap(int A[], int size) {
+  for (int i = size / 2 - 1; i >= 0; i--) {
+    Heapify(A, i, size);
+  }
+}
+
+void HeapSort(int A[], int size) {
+  BuildHeap(A, size);
+  for (int i = size - 1; i > 0; i--) {
+    int temp = A[0];
+    A[0] = A[i];
+    A[i] = temp;
+    Heapify(A, 0, i);
+  }
+}
+
 int main() {
   int size;
   int res = scanf("%d", &size);
@@ -31,6 +45,7 @@ int main() {
     fprintf(stderr, "Error reading size\n");
     return 1;
   }
+
   int *array = malloc(sizeof(int) * size);
   for (int i = 0; i < size; i++) {
     res = scanf("%d", &array[i]);
@@ -41,35 +56,7 @@ int main() {
     }
   }
 
-  printf("pre heap:");
-  for (int i = 0; i < size; i++) {
-    printf("%d ", array[i]);
-  }
-
-  // Build the heap
-  for (int i = size / 2 - 1; i >= 0; i--) {
-    Heapify(array, i, size);
-  }
-
-  printf("\npost heap:");
-  for (int i = 0; i < size; i++) {
-    printf("%d ", array[i]);
-  }
-
-  int heapsize = size;
-  for (int i = size - 1; i >= 0; i--) {
-    int temp = array[i];
-    array[i] = array[1];
-    array[1] = temp;
-    heapsize--;
-    Heapify(array, i, heapsize);
-  }
-
-  printf("\npost sort:");
-
-  for (int i = 0; i < size; i++) {
-    printf("%d ", array[i]);
-  }
+  HeapSort(array, size);
 
   free(array);
   return 0;