(1) Score For Each Problem (Total : 100)

4.1 - 4.20    8pts each
4.22 and 4.24 10pts each

We don't give any bonus for 4.15 which opposed to the instruction in the
key2.pdf.

(2) New Key for 4.24

Sort the remaining n^(1/2) elements in O(n^(1/2)*logn) time. Then merge it
with the sorted array and this can take O(n) time. The total time complexity
is O(n).