string addBinary(string a, string b) {

string res;

int maxLen = a.size() > b.size() ? a.size() : b.size();

unsigned int carry = 0;

for(int i = 0; i < maxLen; i++)

{

unsigned int bitA = i < a.size() ? a[a.size() - i - 1] - '0' : 0;

unsigned int bitB = i < b.size() ? b[b.size() - i - 1] - '0' : 0;

unsigned int total = bitA + bitB + carry;

char sum = '0' + total % 2;

carry = total / 2;

// Add to the beginning of the string

res.insert(0, 1, sum);

}

if(carry)

{

res.insert(0, 1, '1');

}

return res;

}