01_AddBinary.py

# Question link - https://leetcode.com/problems/add-binary/description/?envType=study-plan-v2&envId=top-interview-150

class Solution:
    def addBinary(self, a: str, b: str) -> str:
        res = "" # Result string
        carry = 0 #The number bits should be carry 

        # Reverse the string 
        a , b = a[::-1] , b[::-1]

        for i in range(max(len(a) , len(b))):
            digitA = ord(a[i]) - ord("0") if i < len(a) else 0
            digitB = ord(b[i]) - ord("0") if i < len(b) else 0

            total = digitA + digitB + carry

            # For binary we need to mod 2 
            char = str(total % 2)
            res = char + res
            carry = total // 2

        if carry:
            res = "1" + res

        return res