SRM624 Div1 Easy in python

BuildingHeights.py

class BuildingHeights:
    """ 4000 ** 2 -> T L E"""
    def minimum(self, heights):
        N = len(heights)
        heights = list(heights)
        heights.sort()
        sums = [0 for _ in xrange(N+1)]
        for i in xrange(N):
            sums[i+1] = sums[i] + heights[i]

        result = 0
        for n in xrange(2, N + 1):
            mini = 1000000000
            for l in xrange(N - n + 1):
                mini = min(mini, heights[l + n - 1] * n - (sums[l + n] - sums[l]))
            result ^= mini

        return result