Submission #956284

#	Time	Username	Problem	Language	Result	Execution time	Memory
956284		thangdz2k7	Spring cleaning (CEOI20_cleaning)	C++17	35 / 100	157 ms	49332 KiB

cleaning

// author : HuuHung
// 25.3.2024


#include <bits/stdc++.h>
#define ii pair <int, int>
#define F first
#define S second
#define ll long long
#define lb long double
#define pb push_back
#define vi vector <int>
#define vll vector <ll>
#define Bit(x, i) ((x) >> (i) & 1)
#define Mask(i) (1ll << (i))
#define All(v) (v).begin(), (v).end()

using namespace std;

void maxzi(int &a, int b){
    a = max(a, b);
}

void minzi(int &a, int b){
    a = min(a, b);
}

const int N = 2e5 + 5;
const int mod = 1e9 + 7;
const int LG = 20;

void add(int &a, int b){
    a += b;
    if (a >= mod) a -= mod;
    if (a < 0) a += mod;
}

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

// * end

struct LCA{
    vi st, ed, _lg, high, type, num[2];
    vector <vi> euler, adj;
    int cnt, ans, root, leaf;

    void dfs1(int u, int pa){
        ++ cnt;
        st[u] = cnt;
        euler[cnt].pb(u);
        if (adj[u].size() == 1) type[u] = 1, leaf ++;
        for (int v : adj[u]){
            if (v == pa) continue;
            high[v] = high[u] + 1;
            dfs1(v, u);
            euler[++ cnt].pb(u);
            type[u] ^= type[v];
        }
        ed[u] = cnt;
    }

    int check(int u, int v) {
        return st[u] <= st[v] && ed[v] <= ed[u];
    }

    int min_by_time(int u, int v) {
        return (st[u] < st[v] ? u : v);
    }

    void added(int u, int v){
        adj[u].pb(v);
        adj[v].pb(u);
    }

    void resize(int n){
        leaf = 0;
        ans = n - 1;
        st.resize(n + 3, 0);
        ed.resize(n + 3, 0);
        euler.resize(2 * n + 5);
        high.resize(n + 3, 0);
        type.resize(n + 3, 0);
        num[0].resize(n + 3, 0);
        num[1].resize(n + 3, 0);
        adj.resize(n + 3);
        _lg.resize(2 * n + 5);
        for (int i = 0; i <= 2 * n; ++ i) _lg[i] = log2(i);
    }

    void dfs2(int u, int pa){
        for (int v : adj[u]){
            if (v == pa) continue;
            num[0][v] = num[0][u];
            num[1][v] = num[1][u];
            num[type[v]][v] ++;
            ans += (type[v] ^ 1);
            dfs2(v, u);
        }
    }

    void init(int r){
        root = r;
        cnt = 0;
        high[r] = 1;
        dfs1(r, 0);
        for (int lg = 1; lg < 20; ++lg) {
            for (int i = 1; i + (1 << lg) - 1 <= cnt; ++i)
                euler[i].pb(min_by_time(euler[i][lg - 1], euler[i + (1 << lg - 1)][lg - 1]));
        }
        dfs2(r, 0);
    }

    int get(int u, int v) {
        int L = min(st[u], st[v]);
        int R = max(ed[u], ed[v]);
        int lg = _lg[R - L + 1];
        return min_by_time(euler[L][lg], euler[R - (1 << lg) + 1][lg]);
    }

    int dist(int t, int u, int pa){ return num[t][u] - num[t][pa]; }
} tree;

int deg[N], num[N];
vector <int> s;
vector <int> nw[N];

int process(){
    int ans = tree.ans;
    sort(s.begin(), s.end(), [&](int u, int v){
       return tree.st[u] < tree.st[v];
    });

    int m = s.size();
    for (int i = 1; i < m; ++ i) s.push_back(tree.get(s[i], s[i - 1]));
    s.pb(tree.root);
    sort(s.begin(), s.end(), [&](int u, int v) {
        return tree.st[u] < tree.st[v];
    });
    s.erase(unique(s.begin(), s.end()), s.end());
    reverse(s.begin(), s.end());

    vector <int> stk;
    for (auto u : s){
        while (stk.size() && tree.check(u, stk.back())) {
            int v = stk.back();
            stk.pop_back();
            nw[u].push_back(v);
        }
        stk.push_back(u);
    }

    function <void (int, int)> dfs = [&](int u, int pa){
        for (int v : nw[u]){
            if (v == pa) continue;
            dfs(v, u);
            num[u] ^= num[v];
        }
        if (num[u]) ans += (-tree.dist(0, u, pa) + tree.dist(1, u, pa));
    };

    dfs(tree.root, tree.root);

    for (int u : s) nw[u].clear();
    return ans;
}

void solve(){
    int n, q;
    cin >> n >> q;
    tree.resize(n);
    int root = 1;
    for (int i = 1, u, v; i < n; ++ i){
        cin >> u >> v;
        tree.added(u, v);
        deg[u] ++;
        deg[v] ++;
        if (deg[u] > 1) root = u;
        if (deg[v] > 1) root = v;
    }
    tree.init(root);

    while (q --){
        for (int v : s) num[v] = 0;
        s.clear();
        vector <int> cur;
        int d; cin >> d;
        for (int i = 1; i <= d; ++ i){
            int a; cin >> a;
            if (!num[a]) cur.pb(a);
            num[a] ++;
        }
        int no = 0;
        for (int v : cur){
            num[v] %= 2;
            if ((num[v] && deg[v] > 1) || (!num[v] && deg[v] == 1)) num[v] = 1, s.pb(v);
            if (deg[v] == 1) no ++;
        }
        //cout << no << endl;
        if ((tree.leaf - no + d) % 2) cout << -1 << '\n';
        else cout << process() + d << '\n';
    }
}


int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t = 1;
    while (t --) solve();

    return 0;
}

Compilation message (stderr)

cleaning.cpp: In member function 'void LCA::init(int)':
cleaning.cpp:113:78: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
  113 |                 euler[i].pb(min_by_time(euler[i][lg - 1], euler[i + (1 << lg - 1)][lg - 1]));
      |                                                                           ~~~^~~

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