Which of the following sequences of array elements forms a heap?

An array X of n distinct integers is interpreted as a complete binary tree. The index of the first element of the array is 0. If only the root node does not satisfy the heap property, the algorithm to convert the complete binary tree into a heap has the best asymptotic time complexity of

An implementation of a queue Q, using two stacks S1 and S2, is given below :

void insert(Q, X){
  push(S1, X);
}

void delete(Q){
if(stack - empty(S2)) then {
  if(stack - empty(S1)) then {
   print("Q is empty");
   return;
  }else while (!(stack - empty(S1))){
   X = pop(S1);
   push(S2, X);
 }
 X = pop(S2);
}

Let n insert and $$m( \le n)$$ delete operations be performed in an arbitrary order on an empty queue Q. Let x and y be the number of push and pop operations performed respectively in the process. Which one of the following is true for all m and n?

In a binary tree, the number of internal nodes of degree 1 is 5, and the number of internal nodes of degree 2 is 10. The number of leaf nodes in the binary tree is