Submission #866050

#	Time	Username	Problem	Language	Result	Execution time	Memory
866050		danikoynov	Spring cleaning (CEOI20_cleaning)	C++14	9 / 100	99 ms	41456 KiB

cleaning

#include<bits/stdc++.h>
#define endl '\n'
 
using namespace std;
typedef long long ll;
 
const int maxn = 1e5 + 10;
 
int n, q;
vector < int > adj[maxn];
 
void input()
{
    cin >> n >> q;
    for (int i = 1; i < n; i ++)
    {
        int v, u;
        cin >> v >> u;
        adj[v].push_back(u);
        adj[u].push_back(v);
    }
}
 
int find_leaves(int v, int par)
{
    int cnt = 0, children = 0;
    for (int u : adj[v])
    {
        if (u == par)
            continue;
        cnt += find_leaves(u, v);
        children ++;
    }
 
    if (par == -1 && children == 1)
        cnt ++;
    if (children == 0)
        cnt ++;
    return cnt;
}
 
int parent[maxn], is_leaf[maxn];
int tin[maxn], tout[maxn], timer, occ[2 * maxn], children[maxn];
ll depth[maxn];

void calc(int v, int par)
{
    occ[++ timer] = v;
    tin[v] = timer;
    parent[v] = par;
    is_leaf[v] = true;
    for (int u : adj[v])
    {
        if (u == par)
            continue;
        is_leaf[v] = false;
        depth[u] = depth[v] + 1;
        calc(u, v);
        occ[++ timer] = v;
        children[v] ++;
    }

    tout[v] = timer;
}   


const int maxlog = 21;
int dp[maxlog][maxn * 2], lg[2 * maxn];

void build_sparse_table()
{
    for (int i = 1; i <= timer; i ++)
    {
        lg[i] = lg[i / 2] + 1;
        dp[0][i] = occ[i];
    }

    for (int j = 1; j < maxlog; j ++)
        for (int i = 1; i <= (timer - (1 << j)) + 1; i ++)
        {
            dp[j][i] = dp[j - 1][i + (1 << (j - 1))];
            if (depth[dp[j - 1][i]] < depth[dp[j][i]])
                dp[j][i] = dp[j - 1][i];
        }
}

int get_lca(int v, int u)
{
    int l = tin[v], r = tin[u];
    if (l > r)
        swap(l, r);
    int len = lg[r - l + 1] - 1, lca = dp[len][r - (1 << len) + 1];
    if (depth[dp[len][l]] < depth[lca])
        lca = dp[len][l];
    return lca;
}

ll get_distance(int v, int u)
{
    return depth[v] + depth[u] - 2 * depth[get_lca(v, u)];
}


ll added[maxn];
ll sum[maxn], cnt[maxn];
int all = 0;
void find_depths(int v)
{
    all ++;
    sum[v] = cnt[v] = 0;
    bool leaf = true;
    for (int u : adj[v])
    {   
        if (u == parent[v])
            continue;
        find_depths(u);
        cnt[v] += cnt[u];
        sum[v] += sum[u];
        leaf = false;
    }
 
    sum[v] = sum[v] + added[v] * (depth[v] + 1);
    cnt[v] += added[v];
 
    if (leaf && added[v] == 0)
        sum[v] = sum[v] + depth[v], cnt[v] ++;
 
    ll pairs = cnt[v] / 2;
    if (pairs * 2 == cnt[v])
        pairs --;
    
    sum[v] = sum[v] - pairs * depth[v] * (ll)2;
    cnt[v] -= pairs * 2;
    added[v] = 0;
    ///cout << "state " << v << " " << cnt[v] << " " << sum[v] << endl; 

}
 
int used[maxn];
 
bool cmp(int v, int u)
{
    return tin[v] < tin[u];
}

vector < int > vir[maxn];
ll cnt_on[maxn];

pair < ll, ll > vir_dfs(int v)
{
   
    ll cnt = 0, sum = 0;
    for (int u : vir[v])
    {
        pair < ll, ll > res = vir_dfs(u);
        cnt += res.second;
        sum += res.first;
    }

    cnt = cnt + cnt_on[v];
    sum = sum + cnt_on[v] * depth[v];

    ll pair = cnt / 2;
    cnt -= pair * 2;
    sum = sum - (ll)2 * pair * depth[v];
    ///cout << v << " : " << sum << " : " << cnt << endl;
    return {sum, cnt}; 
}

ll virtual_tree(vector < int > nodes)
{

    if (nodes.empty())
        return 0;
    for (int cur : nodes)
        cnt_on[cur] ++;
    sort(nodes.begin(), nodes.end(), cmp);
    vector < int > nc;
    for (int i = 1; i < nodes.size(); i ++)
    {
        ///cout << get_lca(nodes[i - 1], nodes[i]) << " " << nodes[i - 1] << " " << nodes[i] << endl;
        nc.push_back(get_lca(nodes[i - 1], nodes[i]));
    }
    for (int cur : nc)
        nodes.push_back(cur);
    nc.clear();

    sort(nodes.begin(), nodes.end());
    
    for (int cur : nodes)
    {
        if (nc.empty() || cur != nc.back())
            nc.push_back(cur);
    }
    nodes = nc;
    sort(nodes.begin(), nodes.end(), cmp);

    for (int cur : nodes)
        vir[cur].clear();

    vector < int > st;
    for (int i = 0; i < nodes.size(); i ++)
    {
        ///cout << nodes[i] << " ";
        while (!st.empty() && get_lca(nodes[i], st.back()) != st.back())
            st.pop_back();
        if (!st.empty())
        {
            ///cout << "edge " << st.back() << " " << nodes[i] << endl;
            vir[st.back()].push_back(nodes[i]);
        }
        st.push_back(nodes[i]);
    }
    

    ll ans = vir_dfs(st[0]).first;

    for (int cur : nodes)
        cnt_on[cur] = 0;
    
    return ans;

}
void answer_queries()
{
    int root = 1;
    while(adj[root].size() == 1)
        root ++;
    calc(root, -1);
    int cnt_leaves = 0;
    for (int i = 1; i <= n; i ++)
        cnt_leaves += is_leaf[i];

    int special = -1;
    if (cnt_leaves % 2 == 1)
    {
        
        int ver = 1;
        while(!is_leaf[ver])
            ver ++;
        int last = ver;
        int st = parent[ver];
        while(children[st] == 1)
        {
            last = st;
            st = parent[st];
        }

        int pt = 0;
        while(adj[st][pt] != last)
            pt ++;
        adj[st].erase(adj[st].begin() + pt);
        children[st] --;

        special = ver;
        parent[ver] = st;
    }

    build_sparse_table();

    find_depths(root);
    
        ///cout << sum[1] << " : " << cnt[1] << endl;
    for (int i = 1; i <= q; i ++)
    {
        int d;
        cin >> d;
        unordered_set < int > nodes;
        for (int j = 0; j < d; j ++)
        {
            int x;
            cin >> x;
            nodes.insert(x);
            added[x] ++;
        }

        ll ans = sum[root];
        vector < int > attach;
        for (int cur : nodes)
        {
            if (is_leaf[cur])
            {
                if (cur != special)
                {   
                    ans ++;
                    added[cur] --;
                    ll pairs = added[cur] / 2;
                    added[cur] -= pairs * 2;
                    ans = ans + pairs * 2;
                    ///cout << "here" << added[cur] << endl;
                    if (added[cur] > 0)
                        attach.push_back(cur);
                    ans += added[cur];
        
                }
            }
            else
            {
                ll pairs = added[cur] / 2;
                added[cur] -= pairs * 2;
                ans = ans + pairs * 2;
                if (added[cur] > 0)
                    attach.push_back(cur);
                ans += added[cur];
      
            }
        }

        /**if (special != -1)
        {
            if (added[special] == 0)
            {
                attach.push_back(parent[special]);
                ans = ans + depth[special] - depth[parent[special]];
            }
            else
            {
                attach.push_back(parent[special]);
                ans = ans + depth[special]
            }
        }*/

        if (attach.size() % 2 == 1)
        {
            cout << -1 << endl;
        }
        else
        {
            ans = ans + virtual_tree(attach);
            cout << ans << endl;
        }

        for (int cur : nodes)
            added[cur] = 0;

    }
    
 
 
}
 
void solve()
{
    input();
    answer_queries();
}
 
void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}
int main()
{
    speed();
    solve();
    return 0;
}
 
/**
 7 3
1 2
2 4
4 5
5 6
5 7
3 4
1 4
2 2 4
1 1
 
7 1
1 2
1 3
2 4
2 5
3 6
3 7
8 4 4 5 5 6 6 7 7
*/

Compilation message (stderr)

cleaning.cpp: In function 'll virtual_tree(std::vector<int>)':
cleaning.cpp:179:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  179 |     for (int i = 1; i < nodes.size(); i ++)
      |                     ~~^~~~~~~~~~~~~~
cleaning.cpp:202:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  202 |     for (int i = 0; i < nodes.size(); i ++)
      |                     ~~^~~~~~~~~~~~~~

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