67. Add Binary

Given two binary strings, return their sum (also a binary string).

For example,
a = "11"
b = "1"

Return "100".

用大数加法的思想，按位相加。

class Solution {public:    string addBinary(string a, string b) {        int i=a.size()-1;        int j=b.size()-1;        int t=0;        string c;        while(i>=0&&j>=0){            t+=a[i--]-'0'+b[j--]-'0';            c=char(t%2+'0')+c;            t/=2;        }        while(i>=0){            t+=a[i--]-'0';            c=char(t%2+'0')+c;            t/=2;        }        while(j>=0){            t+=b[j--]-'0';            c=char(t%2+'0')+c;            t/=2;        }        if(t)c=char(t%2+'0')+c;        return c;    }};

又看了看网上大神的代码,学习了。。。

class Solution {public:    string addBinary(string a, string b)     {        string result = "";        int c = 0;        int i = a.size() - 1;        int j = b.size() - 1;                while(i >= 0 || j >=0 ||c ==1)        {            c += i >= 0 ? a[i--] - '0':0;            c += j >= 0 ? b[j--] - '0':0;            result = char( c% 2 + '0') + result;            c /= 2;                }         return result;        }};