#### Gray Codes

N
```/**
* Generates a Gray code sequence for the given number of bits.
* @param {number} n - The number of bits in the Gray code sequence.
* @returns {number[]} - An array of Gray codes in binary format.
* @description
* Gray codes are binary sequences in which two successive values differ in only one bit.
* This function generates a Gray code sequence of length 2^n for the given number of bits.
*
* The algorithm follows these steps:
*
* 1. Initialize an array `grayCodes` to store the Gray codes. Start with [0, 1] for n = 1.
* 2. Iterate from 1 to n:
*    a. Calculate `highestBit` as 2^i, where `i` is the current iteration index.
*    b. Iterate in reverse order through the existing Gray codes:
*       - For each Gray code `code`, add `highestBit | code` to `grayCodes`.
*       - This operation flips a single bit in each existing code, creating new codes.
* 3. Return the `grayCodes` array containing the Gray codes in decimal representation.
*
*resources: [GFG](https://www.geeksforgeeks.org/generate-n-bit-gray-codes/)
* @example
* const n = 3;
* const grayCodes = generateGrayCodes(n);
* // grayCodes will be [0, 1, 3, 2, 6, 7, 5, 4] for n=3.
*/
function generateGrayCodes(n) {
if (n <= 0) {
return 
}

const grayCodes = [0, 1]

for (let i = 1; i < n; i++) {
const highestBit = 1 << i
for (let j = grayCodes.length - 1; j >= 0; j--) {
grayCodes.push(highestBit | grayCodes[j])
}
}

return grayCodes
}

export { generateGrayCodes }
```  