## Discussion Forum

Que. | 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:n+m <= x < 2n and 2m <= y <= n+m |