void idct(complex* v, int n) {
	float k = PI / (2 * n);
	complex* new = (complex*)malloc(sizeof(complex) * n);
	complex * scratch = (complex*)malloc(sizeof(complex) * n);
	complex aux;

	new[0].Re = v[0].Re / (n * 2);
	for (int i = 1; i < n; i++) {
		aux.Im = sin(i * k);
		aux.Re = cos(i * k);
		new[i].Re = (v[n-i].Re * aux.Im + v[i].Re * aux.Re) / (n * 2);
		new[i].Im = (aux.Im * v[i].Re - v[n-i].Re * aux.Re) / (n * 2);
	}

	fft(new, n, scratch);

	for (int i = 0; i < n / 2; i++) {
		v[2 * i].Re = new[i].Re;
		v[2 * i + 1].Re = new[n - 1 - i].Re;
	}

	for (int i = 1; i < n-1; i+=2) {
		aux = v[i];
		v[i] = v[i + 1];
		v[i + 1] = aux;
	}
	free(scratch);
	free(new);
}