Problem:
Maximum Sum Sequence

Given a sequence of numbers a1, a2, a3, ..., an, find the maximum sum of a contiguous subsequence of those numbers. Note that, a subsequence of one element is also a contiquous subsequence.

Input

The input consists of multiple datasets. Each data set consists of:

n
a1
a2
.
.
an

You can assume that 1 ≤ n ≤ 5000 and -100000 ≤ ai ≤ 100000.

The input end with a line consisting of a single 0.

Output

For each dataset, print the maximum sum in a line.

Sample Input

7
-5
-1
6
4
9
-6
-7
13
1
2
3
2
-2
-1
1
2
3
2
1
-2
1
3
1000
-200
201
0

Output for the Sample Input

19
14
1001

Solution in Ruby (judge verdict: Accepted)

# Kadane
module Kadane
  def self.max_subarray(a)
    max_so_far =  max_ending_here = -1.0 / 0
    a.each do |i|
      max_ending_here = [i, max_ending_here + i].max
      max_so_far = [max_so_far, max_ending_here].max
    end
    max_so_far
  end
end

answers = []

while n = gets.to_i
  break if n == 0
  a = []
  n.times { a << gets.to_i }
  answers << Kadane.max_subarray(a)
end

answers.each { |answer| puts answer }