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Key to CSE143 Midterm, Fall 2012 handout #20
1. Method Call Output Produced
------------------------------------------------
mystery(1); 1
mystery(2); 2, 1
mystery(4); 4, 2, 1
mystery(8); 8, 4, 2, 1
mystery(10); 10, 5, 16, 8, 4, 2, 1
2. One possible solution appears below.
public void printDashed(int n) {
if (n < 0) {
System.out.print("-");
printDashed(-n);
} else if (n < 10) {
System.out.print(n);
} else {
printDashed(n / 10);
System.out.print("-" + n % 10);
}
}
3. before after code
-----------------------+-----------------------+-------------------------------
| |
| | q.next.next = p;
p->[1]->[2] | p->[2] | p = p.next;
| | q.next.next.next = null;
| |
q->[3]->[4] | q->[3]->[4]->[1] |
| |
| |
-----------------------+-----------------------+-------------------------------
| |
| | p.next.next = p;
p->[1]->[2] | p->[2]->[1] | p = p.next;
| | p.next.next = null;
| | q.next.next = q;
q->[3]->[4] | q->[4]->[3] | q = q.next;
| | q.next.next = null;
| |
-----------------------+-----------------------+-------------------------------
| |
| | ListNode temp = p.next.next;
p->[1]->[2]->[3] | p->[1]->[4] | temp.next = p.next;
| | p.next = q;
| | q.next = null;
q->[4] | q->[3]->[2] | q = temp;
| | temp.next.next = null;
| |
-----------------------+-----------------------+-------------------------------
4. Statement Output
------------------------------------------------------------
var1.method1(); Peak 1/Cliff 3/Peak 3
var2.method1(); Peak 1/Gorge 3
var3.method1(); Peak 1/Hill 3
var4.method1(); Peak 1/Gorge 3
var5.method1(); Peak 1/Peak 3
var6.method1(); compiler error
var1.method2(); compiler error
var2.method2(); Gorge 2
var3.method2(); compiler error
var1.method3(); Cliff 3/Peak 3
var2.method3(); Gorge 3
var3.method3(); Hill 3
((Gorge)var6).method1(); runtime error
((Cliff)var3).method2(); compiler error
((Gorge)var4).method2(); Gorge 2
((Gorge)var3).method2(); runtime error
((Hill)var3).method2(); Hill 2
((Gorge)var1).method1(); runtime error
((Cliff)var4).method3(); Gorge 3
((Peak)var6).method3(); Cliff 3/Peak 3
5. One possible solution appears below.
public int removeMin(Stack<Integer> s) {
Queue<Integer> q = new LinkedList<Integer>();
int min = s.pop();
q.add(min);
while (!s.isEmpty()) {
int next = s.pop();
if (next < min)
min = next;
q.add(next);
}
while (!q.isEmpty()) {
int next = q.remove();
if (next != min)
s.push(next);
}
while (!s.isEmpty())
q.add(s.pop());
while (!q.isEmpty())
s.push(q.remove());
return min;
}
6. 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 = size * 2;
}
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