MergeSort
MergeSort (Table [1..n])
Split Table in half
Recursively sort each half
Merge two halves together
Merge (T1[1..n],T2[1..n])
i1=1, i2=1
While i1<n, i2<n
   If T1[i1] < T2[i2]
     Next is T1[i1]
     i1++
   Else
     Next is T2[i2]
     i2++
   End If
End While
Merging Cars by key
[Aggressiveness of driver].
Most aggressive goes first.