1.one-line

```
def addBinary(self, a, b):
return bin(int(a, 2) + int(b, 2))[2:]
```

2.solution based on https://leetcode.com/discuss/25593/short-code-by-c

```
def addBinary(self, a, b):
pa, pb, c, res = len(a) - 1, len(b) - 1, 0, ""
while pa >= 0 or pb >=0 or c > 0:
c += 1 if pa >= 0 and a[pa] == '1' else 0
c += 1 if pb >= 0 and b[pb] == '1' else 0
res = str(c % 2) + res
pa, pb, c = pa - 1, pb - 1, c / 2
return res
```