Given an integer, write a function to determine if it is a power of two.

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/**
     * @param {number} n
     * @return {boolean}
     */
    function isPowerOfTwo(n) {
        if (n%2 != 0 && n != 1) return false;
        else if(n < 2 && n != 1) return false;
        else if(n == 2) return true;
        else if(n == 1) return true;
        else
            return isPowerOfTwo(n/2);
    }