*1. A contiguous subsequence of a sequence S is a subsequence made up
of consecutive elements of S. For instance, if S is
5, 15, -30, 10, -5, 40, 10,
then 15, -30, 10 is a contiguous subsequence but 5, 15, 40 is not. On
input a list of numbers, $x_1$, $x_2$, $\cdots$, $x_n$, design a linear time algorithm
to output the contiguous subsequence with maximum sum.
For the preceding example, the answer would be 10, -5, 40, 10, with a
sum of 55.
(Hint: For each j, 1 ≤ j ≤ n, consider contiguous subsequences ending
exactly at position j.)
