leetcode -- Add Binary -- 简单要了解

https://leetcode.com/problems/add-binary/

知道二进制加法原理即可，这里只需要知道进位是除数，余数是结果就行。最后不要忽略reg里面的值

class Solution(object):
    def addBinary(self, a, b):
        """
        :type a: str
        :type b: str
        :rtype: str
        """
        if not a:
            return b
        elif not b:
            return a

        tmp_str = ''.join(['0'] * abs(len(a) - len(b)))
        if tmp_str:
            if len(a) > len(b):
                b = tmp_str + b
            else:
                a = tmp_str + a

        reg = 0
        res = ''
        for i in xrange(len(a) - 1, -1, -1):
            tmp = int(a[i]) + int(b[i]) + reg
            mod, inc = tmp % 2, tmp / 2
            res = str(mod) + res
            #print (reg,tmp, mod, inc, res)
            reg = inc
        if reg != 0:
            res = '1' + res
        return res

看这个博客。整理的解题思路

http://c4fun.cn/blog/2014/03/20/leetcode-solution-02/