67-add-binary

67. Add Binary (Easy) (https://leetcode.com/problems/add-binary/)

Given two binary strings a and b, return their sum as a binary string. Constraints: - 1 <= a.length, b.length <= 10^4 - a and b consist only of ‘0’ or ‘1’ characters.

• Each string does not contain leading zeros except for the zero itself.

function addBinary(a: string, b: string): string {
  const sum = BigInt("0b" + a) + BigInt("0b" + b);
  return sum.toString(2);
}
 
// Local check:
console.log(addBinary("11", "1")); // "100"
console.log(addBinary("1010", "1011")); // "10101"
 
// function addBinary(a: string, b: string): string {
//   let i = a.length - 1;
//   let j = b.length - 1;
//   let carry = 0;
//   let result = "";
 
//   while (i >= 0 || j >= 0 || carry) {
//     const x = i >= 0 ? Number(a[i]) : 0;
//     const y = j >= 0 ? Number(b[j]) : 0;
 
//     const sum = x + y + carry;
 
//     result = (sum % 2) + result;
//     carry = Math.floor(sum / 2);
 
//     i--;
//     j--;
//   }
 
//   return result;
// }

Example 1:
 
    Input: a = "11", b = "1"
    Output: "100"
    Explanation: 11 (binary) = 3, 1 (binary) = 1, 3 + 1 = 4 = 100 (binary)
 
  Example 2:
 
    Input: a = "1010", b = "1011"
    Output: "10101"
    Explanation: 1010 (binary) = 10, 1011 (binary) = 11, 10 + 11 = 21 = 10101 (binary)

bit-manipulation leetcode