/**
 * Adds two binary strings and returns the result as a binary string.
 *
 * @param firstBinaryNo - The first binary string.
 * @param secondBinaryNo - The second binary string.
 * @returns The binary sum of the input strings.
 */
export function addBinary(firstBinaryNo: string, secondBinaryNo: string): string {
    let lengthOfFirstNumber: number = firstBinaryNo.length - 1;
    let lengthOfSecondNumber: number = secondBinaryNo.length - 1;
    let solution: string[] = [];
    let carry: number = 0;

    while ( lengthOfFirstNumber >= 0 || lengthOfSecondNumber >= 0) {
        let sum: number = carry;
        if (lengthOfFirstNumber >= 0) sum += parseInt(firstBinaryNo.charAt(lengthOfFirstNumber));
        if (lengthOfSecondNumber >= 0) sum += parseInt(secondBinaryNo.charAt(lengthOfSecondNumber));
        solution.push((sum % 2).toString());
        carry = Math.floor(sum / 2);
        lengthOfFirstNumber--;
        lengthOfSecondNumber--;
    }

    if (carry !== 0) solution.push(carry.toString());

    return solution.reverse().join('');
}