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Leetcode067-addBinary

Posted on Edited on In Views: Valine:
Solution Report of LeetCode Acceptted

Description

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

The input strings are both non-empty and contains only characters 1 or 0.

Example

Example 1:

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Input: a = "11", b = "1"
Output: "100"

Example 2:
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Input: a = "1010", b = "1011"
Output: "10101"

Solution

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public class Solution {
    public String addBinary(String a, String b) {
        String res = "";
        int i = a.length() - 1, j = b.length() -1, carry = 0;
        while (i >= 0 || j >= 0) {
            int sum = carry;
            if (j >= 0) sum += b.charAt(j--) - '0';
            if (i >= 0) sum += a.charAt(i--) - '0';
            res = (sum % 2) + res;
            carry = sum / 2;
        }
        if (carry != 0) res = carry + res;
        return res;
    }
}