Problem 1.

3

Problem 2.

a. Compiler Error
b. OK, prints "Calling B.foo"
c. OK, prints "Calling C.foo, 0"
d. OK, prints "Calling D.foo(), 0"

Problem 3A.

l.item, copy(l.next)

Problem 3B.

ln1.next = merge(ln1.next, ln2);

ln2.next = merge(ln1, ln2.next);

Problem 3C.

y.next = x.next;
x.next = y;

Problem 4.

s2.push(min);
min = tmp;