Code Golf: Shortest code to find a weighted median?

Question

My try at code golfing.

The problem of finding the minimum value of ∑W_i*|X-X_i| reduces to finding the weighted median of a list of x[i] with weights <

Answer 1

Something like this? O(n) running time.

for(int i = 0; i < x.length; i++)
{
sum += x[i] * w[i];
sums.push(sum);
}

median = sum/2;

for(int i = 0; i < array.length - 1; i++)
{
    if(median > sums[element] and median < sums[element+1]
         return x[i];
    if(median == sums[element])
         return (x[i] + x[i+1])/2
}

Not sure how you can get two answers for the median, do you mean if sum/2 is exactly equal to a boundary?

EDIT: After looking at your formatted code, my code does essentially the same thing, did you want a MORE efficient method?

EDIT2: The search part can be done using a modified binary search, that would make it slightly faster.

index = sums.length /2;
finalIndex = binarySearch(index);

int binarySearch(i)
{
    if(median > sums[i+1])
    {
        i += i/2
        return binarySearch(i);
    }
    else if(median < sums[i])
    {
        i -= i/2
        return binarySearch(i);
    }
    return i;
}

Will have to do some checking to make sure it doesn't go on infinitely on edge cases.