// Hunter Schafer. CSE 143
// Program that demonstrates stack/queue operations

import java.util.*;

public class StackQueueExample {
    public static void main(String[] args) {
        Queue<Integer> q = makeQueue(5);
        Stack<Integer> s = new Stack<Integer>();
        System.out.println("initial q = " + q);
        System.out.println("initial s = " + s);
        System.out.println();

        System.out.println("sum of queue = " + sum(q));
        System.out.println("q after sum = " + q);
        System.out.println();

        // Hunter: Moved the code to move from queue to stack into a method
        queueToStack(q, s);

        System.out.println("after q2s q = " + q);
        System.out.println("after q2s s = " + s);
        System.out.println();

        System.out.println("sum of stack = " + sum(s));
        System.out.println("s after sum= " + s);
    }

    // post: returns a Queue containing the numbers 1 to n
    public static Queue<Integer> makeQueue(int n) {
        Queue<Integer> q = new LinkedList<Integer>();

        for (int i = 1; i <= n; i++) {
            q.add(i);
        }
        return q;
    }

    // post: All values from q moved to s (added in queue order).
    public static void queueToStack(Queue<Integer> q, Stack<Integer> s) {
        // Hunter: Added after lecture
        while (!q.isEmpty()) {
            int n = q.remove();
            s.push(n);
        }
    }

    // post: All values from s moved to q (added in stack order)
    public static void stackToQueue(Stack<Integer> s, Queue<Integer> q) {
        // Hunter: Added after lecture
        while (!s.isEmpty()) {
            int n = s.pop();
            q.add(n);
        }
    }

    // post: returns the sum of the values in q
    public static int sum(Queue<Integer> q) {
        int sum = 0;
        for (int i = 0; i < q.size(); i++) {
            int n = q.remove();
            sum += n;
            q.add(n);
        }
        return sum;
    }

    // pre : s is not null
    // post: returns the sum of the values in s
    public static int sum(Stack<Integer> s) {
        Queue<Integer> q = new LinkedList<Integer>();
        int sum = 0;

        // Hunter: Without size variable, for loops exits early
        int size = s.size();
        for (int i = 0; i < size; i++) {
            int n = s.pop();
            sum += n;
            q.add(n);
        }

        queueToStack(q, s);

        // Must go back and forth in the queue again to get the proper order
        stackToQueue(s, q);
        queueToStack(q, s);
        return sum;
    }
}