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].
class Solution(object):
def convertToBase7(self, num):
"""
:type num: int
:rtype: str
"""
ans=""
if num<0:
neg=True
else:
neg=False
num=abs(num)
while num>=7:
ans+=str(num%7)
num=num//7
ans+=str(num)
if neg:
ans='-'+ans[::-1]
return ans
return ans[::-1]