Which one of the following array represents a binary max-heap ?

Key idea: In a max-heap stored as a 0-based array, for every index i the children are at indices 2i+1 and 2i+2 (if they exist). The max-heap property requires each parent to be greater than or equal to its children.

Check the array [26, 15, 17, 14, 11, 9, 13]:

• Index 0 (value 26): children at indices 1 and 2 are 15 and 17. 26 >= 15 and 26 >= 17, so this satisfies the property.

• Index 1 (value 15): children at indices 3 and 4 are 14 and 11. 15 >= 14 and 15 >= 11, so this satisfies the property.

• Index 2 (value 17): children at indices 5 and 6 are 9 and 13. 17 >= 9 and 17 >= 13, so this satisfies the property.

All parent nodes are greater than or equal to their children, therefore the array [26, 15, 17, 14, 11, 9, 13] represents a binary max-heap.