Interview Question
Software Engineer / DevelopersCountry: Russia
Interview Type: In-Person
c++, implementation
template <typename T>
class TwoStackQueue {
private:
stack<T> in;
stack<T> out;
public:
void enqueue(T v) {
in.push(v);
}
void dequeue() {
if (out.empty()) {
while (!in.empty()) {
out.push(in.top());
in.pop();
}
}
out.pop();
}
T peek() {
if (out.empty()) {
while (!in.empty()) {
out.push(in.top());
in.pop();
}
}
return out.top();
}
unsigned int count() {
return in.size() + out.size();
}
};
import java.util.Stack;
public class QueueUsing2Stacks {
public Stack<Integer> stack1=new Stack<Integer>();
public Stack<Integer> stack2=new Stack<Integer>();
public void enque(int value){ //adding values to queue
stack1.add(value);
}
public Integer deque(){
if(stack1.isEmpty()){ //check if queue is empty or not.
System.out.println("nothing in queue, cannot deque anything");
}
while(!stack1.isEmpty()){
stack2.add(stack1.pop());
}
Integer temp= stack2.pop();
while(!stack2.isEmpty()){
stack1.add(stack2.pop());
}
return temp;
}
public static void main(String [] args){
QueueUsing2Stacks queue=new QueueUsing2Stacks();
queue.enque(5);
queue.enque(3);
queue.enque(2);
queue.enque(1);
System.out.println(queue.deque());
System.out.println(queue.deque());
queue.enque(20);
queue.enque(10);
System.out.println(queue.deque());
System.out.println(queue.deque());
System.out.println(queue.deque());
System.out.println(queue.deque());
} }
- Iuri Sitinschi November 19, 2015