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Key to CSE143 Midterm, Spring 2007 handout #23
1. One possible solution appears below.
public void printSum(ArrayIntList list) {
ArrayIntListIterator i = list.iterator();
if (i.hasNext()) {
System.out.print(i.next());
while (i.hasNext())
System.out.print(" + " + i.next());
}
System.out.println();
}
2. One possible solution appears below.
public void stretch(ArrayList<Integer> list) {
for (int i = 0; i < list.size(); i += 2) {
int n = list.get(i);
list.set(i, n / 2 + n % 2);
list.add(i + 1, n / 2);
}
}
3. Method Call Output Produced
-----------------------------------------------
mystery(7); 7
mystery(38); 838
mystery(194); 49194
mystery(782); 28782
mystery(3842); 2483842
4. One possible solution appears below.
public void rotate() {
if (front != null && front.next != null) {
ListNode temp = front;
front = front.next;
ListNode current = front;
while (current.next != null)
current = current.next;
current.next = temp;
temp.next = null;
}
}
5. Statement Output
------------------------------------------------------------
var1.method1(); Nose 1
var2.method1(); Eye 1/Mouth 1
var3.method1(); Eye 1/Mouth 1
var1.method2(); Mouth 2/Nose 1
var2.method2(); Ear 2
var3.method2(); Mouth 2/Eye 1/Mouth 1
var4.method2(); compiler error
var5.method2(); Mouth 2/Nose 1
var6.method2(); Ear 2
var1.method3(); compiler error
var2.method3(); Ear 3
var3.method3(); compiler error
((Nose)var5).method3(); Nose 3
((Eye)var1).method1(); Nose 1
((Eye)var4).method1(); runtime error
((Nose)var1).method3(); Nose 3
((Mouth)var4).method1(); Mouth 1
((Ear)var5).method3(); runtime error
((Eye)var6).method3(); compiler error
((Mouth)var4).method2(); Mouth 2/Mouth 1
6. One possible solution appears below.
public void reorder(Queue<Integer> q) {
Stack<Integer> s = new ArrayStack<Integer>();
int oldSize = q.size();
for (int i = 0; i < oldSize; i++) {
int n = q.dequeue();
if (n < 0)
s.push(n);
else
q.enqueue(n);
}
int newSize = q.size();
while (!s.isEmpty())
q.enqueue(s.pop());
for (int i = 0; i < newSize; i++)
q.enqueue(q.dequeue());
}
7. One possible solution appears below.
public void mirror() {
int last = 2 * size - 1;
for (int i = 0; i < size; i++)
elementData[last - i] = elementData[i];
size *= 2;
}
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Stuart Reges
Last modified: Fri Sep 16 16:16:07 PDT 2011