Submission #1248222

#	Time	Username	Problem	Language	Result	Execution time	Memory
1248222		Minbaev	Railway (BOI17_railway)	C++20	59 / 100	367 ms	151988 KiB

railway

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("Ofast,unroll-loops")

using namespace std;
using namespace __gnu_pbds;

#define pb      push_back
#define all(x)  x.begin(),x.end()
#define int     long long
#define ar      array
#define mrand(a, b)   uniform_int_distribution<int>(a, b)(rng)

template<class T>bool umax(T &a,T b){if(a<b){a=b;return true;}return false;}
template<class T>bool umin(T &a,T b){if(b<a){a=b;return true;}return false;}

template<class T> using ste = tree<T, null_type, less_equal<T>,
rb_tree_tag, tree_order_statistics_node_update>;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

namespace FAST {
    template<typename T, typename F>
    istream &operator>>(istream &cin, pair<T, F> &p) {
        cin >> p.first >> p.second;
        return cin;
    }

    template<typename T, typename F>
    ostream &operator<<(ostream &cout, pair<T, F> &p) {
        cout << p.first << ' ' << p.second;
        return cout;
    }

    template<typename T>
    istream &operator>>(istream &cin, vector<T> &a) {
    for (T &i: a) cin >> i;
        return cin;
    }

    template<typename T>
    ostream &operator<<(ostream &cout, vector<T> &a) {
          for (T i: a) cout << i << ' ';
        return cout;
    }

    template<typename T>
    istream &operator>>(istream &cin, deque<T> &a) {
        for (T &i: a) cin >> i;
        return cin;
    }

    template<typename T>
    ostream &operator<<(ostream &cout, deque<T> &a) {
        for (T i: a) cout << i << ' ';
        return cout;
    }
}
using namespace FAST;

const int inf = 1e17 + 7;
const int mod = 1e9 + 7;
const int N = 3e5 + 5;
const int md = 998244353;

int binpow(int a, int b, int m){
    if(b == 0)return 1;
    if(b % 2 == 0){
        int c = binpow(a,b/2,m);
        return (c*c)%m;
    }
    return (binpow(a,b-1,m)*a)%m;
}

int divi(int a, int b, int m){
    return (a*(binpow(b,m-2, m)))%m;
}

struct Bit {
    vector<int> b, b2;
    int n;

    Bit(int n) {
        this->n = n + 1;
        b.assign(n + 1, 0);
        b2.assign(n+1, 0);
    }

    void add(vector<int>&b, int idx, int x){
        while(idx <= n){
            b[idx] += x;
            idx += idx & -idx;
        }
    }

    void update(int l, int r, int x){
        add(b, l, x);
        add(b, r+1, -x);
        add(b2, l, x*(l-1));
        add(b2, r+1, -x*r);
    }

    int sum(vector<int>&b, int idx){
        int res = 0;
        while(idx > 0){
            res += b[idx];
            idx -= idx & -idx;
        }
        return res;
    }

    int pref(int idx){
        return sum(b, idx) * idx - sum(b2, idx);
    }

    int get(int l, int r){                  
        return pref(r) - pref(l-1);
    }
};

int n,m,k;
int timer;
int op[N][21];
vector<int>g[N], tin(N), tout(N);
vector<int>sz(N), baty(N);
ste<int>s[N];
ste<int>s2[N];
map<ar<int,2>, int> res, ind;


void dfs(int x, int pr){
    op[x][0] = pr;
    for(int i = 1;i<=20;i++){
        op[x][i] = op[op[x][i-1]][i-1];
    }

    tin[x] = timer++;
    for(auto to:g[x]){
        if(to == pr)continue;
        dfs(to, x);
    }
    tout[x] = timer++;
}

bool isbaty(int a, int b){
    return (tin[a] < tin[b] && tout[b] < tout[a]);
}

int lca(int a, int b){
    if(isbaty(a, b))return a;
    if(isbaty(b, a))return b;

    for(int i = 20;i>=0;i--){
        if(!isbaty(op[a][i], b))a = op[a][i];
    }

    return op[a][0];
}

int find_baty(int x){
    if(baty[x] == x)return x;
    return baty[x] = find_baty(baty[x]);
}

void unin(int a, int b){
    a = find_baty(a);
    b = find_baty(b);

    if(a == b)return;

    if(s[a].size() < s[b].size())swap(a, b);
    baty[b] = a;

    for(auto to:s[b]){
        s[a].insert(to);
    }
}

void ans(int x, int pr){
    for(auto to:g[x]){
        if(to == pr)continue;
        ans(to, x);
        unin(x, to);
    }

    int a = find_baty(x);

    // if(x == 3){
        // for(auto to:s[a])cout << to << " ";
        // cout << "\n";
        // for(auto to:s2[x])cout << to << " ";
        // cout << "\n";
    // }

    for(auto to:s2[x]){
        int in = s[a].order_of_key(to);
        if(0 <= in && in < s[a].size() && *s[a].find_by_order(in) == to){
            s[a].erase(s[a].find_by_order(in));
        }
    }

    if(n <= 10000){
        set<int>st;
        for(auto to:s[a])st.insert(to);
        res[{x, pr}] = st.size();
    }
    else res[{x, pr}] = s[a].size();

}

void solve(){

    cin >> n >> m >> k;

    for(int i = 1;i<=n;i++){
        baty[i] = i;
    }

    for(int i = 2;i<=n;i++){
        int a,b;
        cin >> a >> b;
        ind[{a, b}] = i-1;
        ind[{b, a}] = i-1;
        g[a].pb(b);
        g[b].pb(a);
    }

    dfs(1, 1);
    // cout << isbaty(3, 6) << "\n";
    // cout << op[6][1] << "\n";

    for(int i = 1;i<=m;i++){
        int a;
        cin >> a;
        int last = -1;
        for(int j = 1;j<=a;j++){
            int b;
            cin >> b;
            if(last > -1){
                int u = lca(last, b);
                if(u != last)
                    s[last].insert(i);
                if(u != b)
                    s[b].insert(i);

                s2[u].insert(i);
                if(u != last && u != b)s2[u].insert(i);
            }
            last = b;
        }
        // cout << "\n";
    }

    // for(auto to:s[3])cout << to << " ";
    // cout << "\n";

    ans(1, -1);
    vector<int>opp;
    for(auto to:res){
        if(to.second >= k){
            if(ind[to.first] == 0)continue;
            opp.pb(ind[to.first]);
        }
        // cout << to.first[0] << " " << to.first[1] << " " << to.second << "\n";
    }

    sort(all(opp));
    cout << opp.size() << "\n";
    cout << opp << "\n";

}
/*

*/
 signed main()
{
//  freopen("seq.in", "r", stdin);
//  freopen("seq.out", "w", stdout);
    ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL);
    int tt=1; //cin >> tt;
    while(tt--)solve();

}

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 0 / 16
• Subtask 6: 0 / 25