Submission #879556

#	Time	Username	Problem	Language	Result	Execution time	Memory
879556		Shayan86	Spring cleaning (CEOI20_cleaning)	C++14	100 / 100	162 ms	39624 KiB

cleaning

#include <bits/stdc++.h>
using namespace std;

#pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
// Ofast, O0, O1, O2, O3, unroll-loops, fast-math, trapv

typedef long long ll;
typedef pair<ll, ll> pll;
typedef pair<int, int> pii;

#define Mp          make_pair
#define sep         ' '
#define endl        '\n'
#define F	        first
#define S	        second
#define pb          push_back
#define all(x)      (x).begin(),(x).end()
#define kill(res)	cout << res << '\n', exit(0);
#define set_dec(x)	cout << fixed << setprecision(x);
#define fast_io     ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define file_io     freopen("input.txt", "r", stdin) ; freopen("output.txt", "w", stdout);

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const ll L = 20;
const ll N = 1e5 + 50;
const ll Mod = 1e9 + 7;

ll n, q, r, sz[N], cnt[N], h[N], sum[N], par[N][L], st[N], timer, upd[N], head[N];

vector<int> adj[N];

void dfs(int v, int p = 0){
    par[v][0] = p;
    for(int i = 1; i < L; i++){
        if(!par[v][i-1]) break;
        par[v][i] = par[par[v][i-1]][i-1];
    }
    
    sz[v] = 1;
    st[v] = ++timer;
    for(int u: adj[v]){
        if(u == p) continue;
        h[u] = h[v] + 1; dfs(u, v);
        sz[v] += sz[u]; cnt[v] += cnt[u];
    }
    if(sz[v] == 1) cnt[v]++;
}

int getPar(int v, int k){
    for(int i = 0; i < L; i++){
        if(k >> i & 1) v = par[v][i];
    }
    return v;
}

int lca(int u, int v){
    if(h[v] < h[u]) swap(u, v);
    v = getPar(v, h[v] - h[u]);
    if(u == v) return v;

    for(int i = L-1; i >= 0; i--){
        if(par[v][i] != par[u][i]){
            v = par[v][i]; u = par[u][i];
        }
    }
    return par[v][0];
}

void pre(int v, int p = 0){
    sum[v] = sum[p] + (cnt[v] % 2);
    for(int u: adj[v]){
        if(u != p) pre(u, v);
    }
}

bool cmp(int i, int j){
    return st[i] < st[j];
}

int main(){
    fast_io;

    cin >> n >> q;

    int u, v;
    for(int i = 1; i < n; i++){
        cin >> u >> v;
        adj[u].pb(v);
        adj[v].pb(u);
    }

    r = 1;
    while(adj[r].size() == 1) r++;

    dfs(r); pre(r);

    ll ans = 2 * (n-1);
    for(int i = 1; i <= n; i++) if(i != r) ans -= (cnt[i] % 2);
    //cout << ans << endl;

    while(q--){
        int d, x; cin >> d;

        vector<int> vec, vert;
        for(int i = 1; i <= d; i++){
            cin >> x; vec.pb(x); upd[x]++;
        }

        sort(all(vec), cmp);
        vec.resize(unique(all(vec)) - vec.begin());

        for(int i: vec) if(adj[i].size() == 1) upd[i]--;

        set<pii> ms;
        for(int i: vec) ms.insert(Mp(st[i], i));

        while(ms.size() > 1){
            auto lst = ms.end();
            auto lst1 = lst; lst1--;
            auto lst2 = lst1; lst2--;

            int ulv = lca(lst1 -> S, lst2 -> S);
            head[lst1 -> S] = ulv;
            vert.pb(lst1 -> S);

            ms.erase(lst1);
            ms.insert(Mp(st[ulv], ulv));
        }
        vert.pb(ms.begin() -> S); 
        if(vert.back() != r) head[vert.back()] = r;

        for(int i: vert){
            if(head[i]) upd[head[i]] += upd[i];
        }

        ll res = ans;
        for(int i: vert){
            //cout << i << sep << head[i] << sep << upd[i] << endl;
            if(!head[i]) continue;
            if(upd[i] % 2){
                res += sum[i] - sum[head[i]];
                res -= h[i] - h[head[i]] - (sum[i] - sum[head[i]]);
            }
        }

        if((cnt[r] + upd[r]) % 2) cout << -1 << endl;
        else cout << res + d << endl;

        for(int i: vert){
            head[i] = 0; upd[i] = 0;
        }
        upd[r] = 0;
    }

}

• Subtask 1: 0 / 0
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 16 / 16
• Subtask 5: 19 / 19
• Subtask 6: 17 / 17
• Subtask 7: 30 / 30