maximum subarray of an array with integers [duplicate]

Answer 1

I have made a function for a little more general problem:

• Find maximum sum subarray (meaning its bounds and sum, not only the sum)
• If two subarrays have equal sums then pick the shorter one
• If two equally long subarrays have equal sums then pick the one that appears first.

Function is based on Kadane's algorithm and it runs in O(n) time. Basically, this is it:

function MaxSumSubarray(a, n, start out, len out)
    -- a - Array
    -- n - Length of the array
    -- start - On output starting position of largest subarray
    -- len - On output length of largest subarray
    -- Returns sum of the largest subarray
begin

    start = 0
    len = 1
    int sum = a[0]

    curStart = 0
    curLen = 1
    curSum = a[0]

    for i = 2 to n
        begin
            if a[i] >= curSum + a[i] then
                begin
                    curStart = i
                    curLen = 1
                    curSum = a[i]
                end
            else
                begin
                    curLen = curLen + 1
                    curSum = curSum + a[i]
                end

            if (curSum > sum) OR
               (curSum = sum AND curLen < len) OR
               (curSum = sum AND curLen = len AND curStart < start) then
               begin
                    start = curStart
                    len = curLen
                    sum = curSum
                end

        end

    return sum

end

I've uploaded the whole solution in C#, with analysis and examples, in this article: Maximum Sum Subarray