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 (<=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?
(A) n+m <= x < 2n and 2m <= y <= n+m
(B) n+m <= x < 2n and 2m<= y <= 2n
(C) 2m <= x < 2n and 2m <= y <= n+m
(D) 2m <= x <2n and 2m <= y <= 2n
Answer: (A)
Explanation: Same as https://www.geeksforgeeks.org/data-structures-queue-question-10/amp/
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