Add Binary Strings InterviewBit Solution

Problem: Add Binary Strings

Given two binary strings, return their sum (also a binary string).

a = "100" -> 4 in decimal
 b = "11" -> 3 in decimal
 Return a + b = “111” -> 7 in decimal

How will you add two binary numbers on paper? Just try implementing that approach.

O(N), where N is the size of input string.