RT

void FFT(Comp *now_f,ll now_l,ll op){
	if(now_l==1)return;
	Comp g[now_l>>1],h[now_l>>1];
	for(int i=0;i<now_l;i+=2)g[i/2]=now_f[i],h[i/2]=now_f[i+1];
	FFT(g,now_l/2,op),FFT(h,now_l/2,op);
	Comp cur(1,0),step(cos(2*pi/now_l),sin(2*pi*op/now_l));
	for(int i=0;i<now_l/2;i++){
		now_f[i]=g[i]+cur*h[i];
		now_f[i+now_l/2]=g[i]-cur*h[i];
		cur*=step;
	}
	return;
}

不知道错哪了