Sum of a sequence

题意

题解1

def sequence_sum(begin_number, end_number, step):
    #your code here
    if begin_number > end_number:
        return 0
    sum = 0
    num = begin_number
    while num <= end_number:
        sum += num
        num += step
    return sum

def sequence_sum(begin_number, end_number, step):
    #your code here
    if begin_number > end_number:
        return 0
    sum = 0
    num = begin_number
    while num <= end_number:
        sum += num
        num += step
    return sum

题解2

利用python的range结构

def sequence_sum(begin_number, end_number, step):
    return sum(range(begin_number, end_number + 1, step))