[leetcode: Python]504. Base 7

Given an integer, return its base 7 string representation.

Example 1:

Input: 100
Output: "202"

Example 2:

Input: -7
Output: "-10"

Note: The input will be in range of

[-1e7, 1e7]

.

实现七进制

方法一：68ms

class Solution(object):
def convertToBase7(self, num):
"""
:type num: int
:rtype: str
"""
s = ''
if num == 0:
return '0'
sig = 0
if num < 0:
num = abs(num)
sig = 1
c = 0
while num:
num, c = divmod(num, 7)
s = str(c) + s
if sig == 1:
return '-' + s
return s

方法二：56ms

class Solution(object):
def convertToBase7(self, num):
"""
:type num: int
:rtype: str
"""
if not num:
return '0'
ans=[]
sgn='-' if num<0 else ''
num=abs(num)
while num:
ans.append(str(num%7))
num/=7
return sgn+''.join(ans[::-1])

方法三：36ms

class Solution(object):
def convertToBase7(self, num):
if num==0:
return "0"
res=''
n=abs(num)
while n:
res=str(n%7)+res
n//=7
return res if num>0 else '-'+res