Kanade's Algorithm to find maximum subarray sum
var MIN = -1000000000000;
function maxSubArraySum(a)
{
var max_so_far = MIN, max_ending_here = 0;
for(var i = 0; i < a.length; i++)
{
max_ending_here = max_ending_here + a[i];
if(max_so_far < max_ending_here) max_so_far = max_ending_here;
if(max_ending_here < 0) max_ending_here = 0;
}
return max_so_far;
}