莫比烏斯全家桶

ll prime[maxn],mob[maxn],vis[maxn],cnt;

void Mobius(){
    memset(prime,0,sizeof(prime));
    memset(mob,0,sizeof(mob));
    memset(vis,0,sizeof(vis));
    mob[1] = 1;
    cnt = 0;
    for(ll i = 2;i < maxn; i++){
        if(!vis[i]){
            prime[cnt++] = i;
            mob[i] = -1;
        }
        for
 
(ll j = 0;j < cnt&&i*prime[j] < maxn;j++){
            vis[i*prime[j]] = 1;
            if(i%prime[j]) mob[i*prime[j]] = -mob[i];
            else{
                mob[i*prime[j]] = 0;
                break;
            }
        }
    }
}