67. Add Binary

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

For example,
a = "11"
b = "1"
Return "100".

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Solution:

Tips:

easy

Java Code:

public class Solution {    public String addBinary(String a, String b) {        int i = a.length() - 1;        int j = b.length() - 1;        int carry = 0;        StringBuilder result = new StringBuilder();        while (i >= 0 || j >= 0) {            char ac = i >= 0 ? a.charAt(i) : '0';            char bc = j >= 0 ? b.charAt(j) : '0';                        int sum = (ac - '0') + (bc - '0') + carry;            result.append(sum % 2);            carry = sum / 2;            i--;            j--;        }                if (carry > 0) {            result.append(1);        }                return new String(result.reverse());    }}