Given two binary strings a and b, return their sum as a binary string.
Example 1:
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Input: a = "11", b = "1"
Output: "100"
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Example 2:
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Input: a = "1010", b = "1011"
Output: "10101"
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Constraints:
1 <= a.length, b.length <= 104a and b consist only of '0' or '1' characters.- Each string does not contain leading zeros except for the zero itself.
解题思路
直接按照进位处理即可。
朴素解法
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class Solution(object):
def addBinary(self, a, b):
"""
:type a: str
:type b: str
:rtype: str
"""
_up=0
ans=[]
a,b=list(a),list(b)
while len(a)!=0 and len(b)!=0:
_a=int(a.pop(-1))
_b=int(b.pop(-1))
_sum=_a+_b+_up
if _sum>=2:
ans.append(_sum%2)
_up=1
else:
ans.append(_sum)
_up=0
if len(a)!=0:
while len(a)!=0:
_a=int(a.pop(-1))
_sum=_a+_up
if _sum>=2:
ans.append(_sum%2)
_up=1
else:
ans.append(_sum)
_up=0
elif len(b)!=0:
while len(b)!=0:
_b=int(b.pop(-1))
_sum=_b+_up
if _sum>=2:
ans.append(_sum%2)
_up=1
else:
ans.append(_sum)
_up=0
if _up!=0:
ans.append(_up)
return ''.join([str(x) for x in ans[::-1]])
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性能分析：
Runtime: 32 ms, faster than 40.49% of Python online submissions for Add Binary.
Memory Usage: 13.7 MB, less than 6.13% of Python online submissions for Add Binary.
调包解法：
直接把二进制转为10进制求和再转回二进制
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res = int(a, 2) + int(b, 2)
res_str = str(bin(res))
res_len = len(res_str)
return res_str[2:res_len]
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