C++

1 class Solution { 2 public: 3     /** 4      * @param a a number 5      * @param b a number 6      * @return the result 7      */ 8     string addBinary(string& a, string& b) { 9         // Write your code here10         if (a == "0") {11             return b;12         }13         if (b == "0") {14             return a;15         }16         string result;17         int carry = 0;18         int ai, bj, sum;19         char val;20         for (int i = a.size()-1, j = b.size()-1; i >= 0 || j >= 0; i--, j--) {21             ai = i >= 0?a[i]-'0':0;22             bj = j >= 0?b[j]-'0':0;23             sum = ai+bj+carry;24             val = sum%2?'1':'0';25             carry = sum/2;26             result.insert(result.begin(), val);27         }28         if (carry == 1) {29             result.insert(result.begin(), '1');30         }31         return result;32     }33 };