Submission #908538

#	Time	Username	Problem	Language	Result	Execution time	Memory
908538		GrindMachine	Special graph (IZhO13_specialg)	C++17	100 / 100	56 ms	21188 KiB

specialg

#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;
}

• Subtask 1: 100 / 100