两链表和

def two_sum(l, l2):
    result = []
    carry = 0
    # 最大循环
    le1, le2 = len(l), len(l2)
    n = le1 if le1 > le2 else le2
    for i in range(n):
        try:
            n1 = l[i]
        except IndexError:
            n1 = 0
        try:
            n2 = l2[i]
        except IndexError:
            n2 = 0
        sum = n1 + n2 + carry
        result.append(sum % 10)
        # 进位
        carry = int(sum / 10)
    # 加上最后的进位
    if carry > 0:
        result.append(carry)
    return result


if __name__ == '__main__':
    l = [9, 9, 9, 9, 9, 9, 9]
    l2 = [9, 9, 9, 9]
    r = two_sum(l, l2)
    print(r)