Rinne Loves Sequence

Rinne Loves Sequence

思路

写完后看了一下ac代码，果然就我的最暴力了。

代码

/*
  Author : lifehappy
*/
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int N = 5e5 + 10;

int prime[N], mu[N], num[N], n, cnt;

bool st[N], vis[N];

vector<int> fac[N];

void init() {
    mu[1] = 1;
    for(int i = 2; i < N; i++) {
        if(!st[i]) {
            prime[++cnt] = i;
            mu[i] = -1;
        }
        for(int j = 1; j <= cnt && 1ll * i * prime[j] < N; j++) {
            st[i * prime[j]] = 1;
            if(i % prime[j] == 0) {
                break;
            }
            mu[i * prime[j]] = -mu[i];
        }
    }
    for(int i = 1; i < N; i++) {
        for(int j = i; j < N; j += i) {
            fac[j].push_back(i);
        }
    }
}

int main() {
    // freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
    // ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
    init();
    scanf("%d", &n);
    ll ans = 0;
    for(int i = 1; i <= n; i++) {
        int op, x;
        scanf("%d %d", &op, &x);
        if(op == 1) {
            if(vis[x]) continue;
            vis[x] = 1;
            for(auto d : fac[x]) {
                ans += mu[d] * num[d];
                num[d]++;
            }
        }
        else if(op == 2) {
            if(!vis[x]) continue;
            vis[x] = 0;
            for(auto d : fac[x]) {
                num[d]--;
                ans -= mu[d] * num[d];
            }
        }
        else {
            printf("%lld\n", ans);
        }
    }
    return 0;
}