Exponentiation done recursive & iterative with Bitwise

My solution to a “Daily Coding Problem” that I received in my mail today.

Implement integer exponentiation. That is, implement the pow(x, y) function, where x and y are integers and returns x^y.

Do this faster than the naive method of repeated multiplication.

For example, pow(2, 10) should return 1024.

Here’s my solution in Typescript. I will be honest, I can’t fully visualise the iterative solution in my head. So while I solved this, not sure how will I solve the next problem that needs some bit-shifting. It’s been some time so, I need some practice with my bitwise operations

//iterartive and more efficient solution space-wise
sixtyOne(x: number, y: number) {
    //function to calculate power
    let res = 1;
    while (y> 0) {
        //if y is odd multiply, 
        //x with result
        if((y & 1) == 1) {
            res = res * x;
        }
        //n must be even now
        y = y >> 1;
        x = x * x;
    }
    return res;
}
//less efficient solution space-wise
sixtyOneRecursive(x: number, y: number): number {
    if(y == 0) {
        return 1;
    } else if(y % 2 == 0) {
        return this.sixtyOneRecursive(x, Math.floor(y/2)) * this.sixtyOneRecursive(x, Math.floor(y/2));
    } else {
        return x * this.sixtyOneRecursive(x, Math.floor(y/2)) * this.sixtyOneRecursive(x, Math.floor(y/2));
    }
}

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