// Helene Martin, CSE 143
// Demonstrates basic usage of stacks and queues
import java.util.*;

public class StacksQueues {
	public static void main(String[] args) {
		Stack<String> tas = new Stack<String>();
		tas.push("Molly"); // bottom of stack
		tas.push("Zack");
		tas.push("Andrew"); // top of stack
		System.out.println(tas);
		System.out.println(tas.pop()); // Andrew (top)
		System.out.println(tas);

		Stack<Integer> nums = createRandomStack(12);
		System.out.println("Random stack: " + nums);
		int max = max(nums);
		System.out.println("Max: " + max);
		System.out.println("Stack after max: " + nums);
		System.out.println();

		Queue<String> taQueue = new LinkedList<String>();
		taQueue.add("Molly"); // front of queue
		taQueue.add("Zack");
		taQueue.add("Andrew"); // back of queue
		System.out.println(taQueue);
		System.out.println(taQueue.remove()); // Molly (front)
		System.out.println(taQueue);

		Queue<Integer> q = createRandomQueue(12);
		System.out.println("Random queue: " + q);
		int sum = sum(q);
		System.out.println("Sum " + sum);
		System.out.println("Queue after sum: " + q);
	}

	// Creates and returns a stack with the specified number of random values
	// in the range 0-29.
	// pre: size >= 0
	public static Stack<Integer> createRandomStack(int size) {
		Stack<Integer> nums = new Stack<Integer>();
		Random r = new Random();
		for (int i = 0; i < size; i++) {
			nums.push(r.nextInt(30));
		}
		return nums;
	}

	// Creates and returns a queue with the specified number of random values
	// in the range 0-29.
	// pre: size >= 0
	public static Queue<Integer> createRandomQueue(int size) {
		Queue<Integer> q = new LinkedList<Integer>();
		Random r = new Random();
		for (int i = 0; i < size; i++) {
			q.add(r.nextInt(30));
		}
		return q;
	}

	// Returns the max of values in a stack of integers.
	// post: stack is unchanged.
	public static int max(Stack<Integer> nums) {
		int max = nums.peek();
		Stack<Integer> backup = new Stack<Integer>();

		while (!nums.isEmpty()) {
			int value = nums.pop();
			backup.push(value); // save
			if (value > max) {
				max = value;
			}
		}

		// restore the stack
		while (!backup.isEmpty()) {
			nums.push(backup.pop());
		}
		return max;
	}

	// Returns the sum of all values in a queue of integers.
	// post: queue is unchanged
	public static int sum(Queue<Integer> q) {
		int sum = 0;

		for (int i = 0; i < q.size(); i++) {
			int value = q.remove();
			sum += value;
			q.add(value); // can use the queue itself for storage
		}

		// while (!q.isEmpty()) {
		// sum += q.remove();
		// }
		return sum;
	}
}