67. Add Binary Leetcode Python

For example,

a = "11"

b = "1"

Return "100".

这题的做法和前面一题plus one 一样，区别在于需要将两个string先相加，再判断是否要进位。

直接上代码吧。

class Solution:
    # @param a, a string
    # @param b, a string
    # @return a string
    def addBinary(self, a, b):
        a=list(a)
        b=list(b)
        for i in range(len(a)):
            a[i]=int(a[i])
        for i in range(len(b)):
            b[i]=int(b[i])
        lena=len(a)
        lenb=len(b)
        if lena<lenb:
            a,b=b,a
        itera=len(a)-1
        iterb=len(b)-1
        while itera>=0 and iterb>=0:
            a[itera]+=b[iterb]
            itera-=1
            iterb-=1
        for i in reversed(range(len(a))):
            digit=a[i]%2
            carry=a[i]/2
            a[i]=digit
            if i>0:
                a[i-1]+=carry
        if carry==1:
            a.insert(0,1)
        for i in range(len(a)):
            a[i]=str(a[i])
        return "".join(a)