import sysclass mergesort():    def merge_sort(self, A, p, r):        if p < r:            q = (p + r) / 2            self.merge_sort(A, p, q)            self.merge_sort(A, q+1, r)            self.merge(A, p, q, r)            return A    def merge(self, A, p, q, r):        n1 = q - p + 1        n2 = r - q        L = [0 for i in range(n1+1)]        R = [0 for i in range(n2+1)]        for i in range(n1):            L[i] = A[p+i]        for j in range(n2):            R[j] = A[q+j+1]        L[n1] = sys.maxint        R[n2] = sys.maxint        i = 0; j = 0        for k in range(p, r):            if L[i] <= R[j]:                A[k] = L[i]                i += 1            else:                A[k] = R[j]                j += 1sort = mergesort()A = [1,3,5,7,9,2,4,6,8,10]print sort.merge_sort(A, 0, len(A)-1)