Add Binary
class Solution {
public:
string addBinary(string a, string b) {
int carry = 0;
int i = a.size() - 1;
int j = b.size() - 1;
string result;
while(i >= 0 && j >= 0){
int r = a[i] - '0' + b[j] - '0' + carry;
carry = r / 2;
result.insert(result.begin(), r%2 + '0');
i--;
j--;
}
while(i >= 0){
int r = a[i] - '0' + carry;
carry = r / 2;
result.insert(result.begin(), r%2 + '0');
i--;
}
while(j >= 0){
int r = b[j] - '0' + carry;
carry = r / 2;
result.insert(result.begin(), r%2 + '0');
j--;
}
while(carry > 0){
int r = carry;
carry = r / 2;
result.insert(result.begin(), r%2 + '0');
}
return result;
}
};