Problem
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 1:
Input: a = "11", b = "1"
Output: "100"
Example 2:
Input: a = "1010", b = "1011"
Output: "10101"
Solution
/**
* @param {string} a
* @param {string} b
* @return {string}
*/
var addBinary = function(a, b) {
var len1 = a.length;
var len2 = b.length;
var max = Math.max(len1, len2);
var res = '';
var carry = 0;
var val = 0;
for (var i = 0; i < max; i++) {
val = Number(a[len1 - 1 - i] || 0) + Number(b[len2 - 1 - i] || 0) + carry;
carry = Math.floor(val / 2);
res = (val % 2) + res;
}
if (carry) res = 1 + res;
return res;
};
Explain:
nope.
Complexity:
- Time complexity : O(n).
- Space complexity : O(1).