Method reverseBits

src/main/java/com/thealgorithms/maths/FFT.java:270–278

This function reverses the bits of a number. It is used in Cooley-Tukey FFT algorithm. E.g. num = 13 = 00001101 in binary log2n = 8 Then reversed = 176 = 10110000 in binary More info: https://cp-algorithms.com/algebra/fft.html https://www.geeksforgeeks.org/write-an-efficient-c-program-to-r

(int num, int log2n)

     * @return The reversed number
     */
    private static int reverseBits(int num, int log2n) {
        int reversed = 0;
        for (int i = 0; i < log2n; i++) {
            if ((num & (1 << i)) != 0) {
                reversed |= 1 << (log2n - 1 - i);
            }
        }
        return reversed;
    }

    /**
     * This method pads an ArrayList with zeros in order to have a size equal to