#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a,b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a,b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
/*
*/
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
template<typename T>
struct fenwick {
int siz;
vector<T> tree;
fenwick() {
}
fenwick(int n) {
siz = n;
tree = vector<T>(n + 1);
}
int lsb(int x) {
return x & -x;
}
void build(vector<T> &a, int n) {
for (int i = 1; i <= n; ++i) {
int par = i + lsb(i);
tree[i] += a[i];
if (par <= siz) {
tree[par] += tree[i];
}
}
}
void pupd(int i, T v) {
while (i <= siz) {
tree[i] += v;
i += lsb(i);
}
}
T sum(int i) {
T res = 0;
while (i) {
res += tree[i];
i -= lsb(i);
}
return res;
}
T query(int l, int r) {
if (l > r) return 0;
T res = sum(r) - sum(l - 1);
return res;
}
};
struct DSU {
vector<int> par, rankk, siz;
DSU() {
}
DSU(int n) {
init(n);
}
void init(int n) {
par = vector<int>(n + 1);
rankk = vector<int>(n + 1);
siz = vector<int>(n + 1);
rep(i, n + 1) create(i);
}
void create(int u) {
par[u] = u;
rankk[u] = 0;
siz[u] = 1;
}
int find(int u) {
if (u == par[u]) return u;
else return par[u] = find(par[u]);
}
bool same(int u, int v) {
return find(u) == find(v);
}
void merge(int u, int v) {
u = find(u), v = find(v);
if (u == v) return;
if (rankk[u] == rankk[v]) rankk[u]++;
if (rankk[u] < rankk[v]) swap(u, v);
par[v] = u;
siz[u] += siz[v];
}
};
vector<ll> adj[N];
vector<bool> vis(N);
vector<ll> tin(N), tout(N);
vector<ll> depth(N);
vector<ll> root(N);
ll timer = 1;
void dfs1(ll u, ll r){
vis[u] = 1;
tin[u] = timer++;
root[u] = r;
trav(v,adj[u]){
if(vis[v]) conts;
depth[v] = depth[u]+1;
dfs1(v,r);
}
tout[u] = timer-1;
}
void solve(int test_case)
{
ll n; cin >> n;
vector<ll> a(n+5);
rep1(i,n) cin >> a[i];
rep1(i,n){
if(!a[i]){
a[i] = i;
}
}
queue<ll> q;
vector<bool> bad(n+5);
vector<ll> indeg(n+5);
rep1(i,n){
adj[a[i]].pb(i);
indeg[a[i]]++;
}
rep1(i,n){
if(indeg[i] == 0){
q.push(i);
}
}
while(!q.empty()){
ll u = q.front();
q.pop();
bad[u] = 1;
indeg[a[u]]--;
if(indeg[a[u]] == 0){
q.push(a[u]);
}
}
vector<ll> cyc_id(n+5), cyc_pos(n+5), cyc_siz(n+5);
ll ptr = 0;
rep1(i,n){
if(bad[i] or vis[i]) conts;
ll j = i;
vector<ll> roots;
ptr++;
ll curr_pos = 1;
while(!vis[j]){
vis[j] = 1;
roots.pb(j);
cyc_id[j] = ptr;
cyc_pos[j] = curr_pos++;
j = a[j];
}
cyc_siz[ptr] = sz(roots);
trav(r,roots){
dfs1(r,r);
}
}
fenwick<ll> fenw[ptr+5];
rep1(i,ptr){
fenw[i] = fenwick<ll>(cyc_siz[i]);
}
ll m; cin >> m;
vector<array<ll,3>> queries(m+5);
vector<bool> rem(n+5);
rep1(i,m){
ll t; cin >> t;
if(t == 1){
ll u; cin >> u;
queries[i] = {t,u,-1};
rem[u] = 1;
}
else{
ll u,v; cin >> u >> v;
queries[i] = {t,u,v};
}
}
DSU dsu(n+5);
auto activate = [&](ll u){
dsu.merge(u,a[u]);
if(!bad[u]){
ll id = cyc_id[u];
ll pos = cyc_pos[u];
fenw[id].pupd(pos,1);
}
};
rep1(i,n){
if(!rem[i]){
activate(i);
}
}
vector<ll> ans(m+5);
rev(i,m,1){
auto [t,u,v] = queries[i];
if(t == 1){
activate(u);
}
else{
if(!dsu.same(u,v)){
ans[i] = -1;
conts;
}
if(bad[v]){
if(!(tin[v] <= tin[u] and tout[v] >= tout[u])){
ans[i] = -1;
conts;
}
ans[i] = depth[u]-depth[v];
conts;
}
ll rootu = root[u];
if(cyc_id[rootu] != cyc_id[v]){
ans[i] = -1;
conts;
}
ans[i] = depth[u];
ll id = cyc_id[rootu];
ll l = cyc_pos[rootu], r = cyc_pos[v];
if(l <= r){
if(fenw[id].query(l,r-1) == r-l){
ans[i] += r-l;
}
else{
ans[i] = -1;
}
}
else{
ll siz = cyc_siz[id];
ll sum = fenw[id].query(l,siz)+fenw[id].query(1,r-1);
ll len = siz-l+r;
if(sum == len){
ans[i] += len;
}
else{
ans[i] = -1;
}
}
}
}
rep1(i,m){
if(queries[i][0] == 2){
cout << ans[i] << endl;
}
}
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
5980 KB |
Output is correct |
| 2 |
Correct |
4 ms |
6236 KB |
Output is correct |
| 3 |
Correct |
4 ms |
6236 KB |
Output is correct |
| 4 |
Correct |
5 ms |
6232 KB |
Output is correct |
| 5 |
Correct |
5 ms |
6492 KB |
Output is correct |
| 6 |
Correct |
7 ms |
6748 KB |
Output is correct |
| 7 |
Correct |
7 ms |
7004 KB |
Output is correct |
| 8 |
Correct |
8 ms |
7012 KB |
Output is correct |
| 9 |
Correct |
8 ms |
7024 KB |
Output is correct |
| 10 |
Correct |
8 ms |
7000 KB |
Output is correct |
| 11 |
Correct |
49 ms |
20412 KB |
Output is correct |
| 12 |
Correct |
39 ms |
16708 KB |
Output is correct |
| 13 |
Correct |
54 ms |
19100 KB |
Output is correct |
| 14 |
Correct |
38 ms |
15916 KB |
Output is correct |
| 15 |
Correct |
41 ms |
17184 KB |
Output is correct |
| 16 |
Correct |
41 ms |
16948 KB |
Output is correct |
| 17 |
Correct |
52 ms |
21040 KB |
Output is correct |
| 18 |
Correct |
53 ms |
21188 KB |
Output is correct |
| 19 |
Correct |
56 ms |
21188 KB |
Output is correct |
| 20 |
Correct |
47 ms |
20404 KB |
Output is correct |
