Submission #866007

#	Time	Username	Problem	Language	Result	Execution time	Memory
866007		danikoynov	Spring cleaning (CEOI20_cleaning)	C++14	34 / 100	233 ms	33548 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 sub[maxn], parent[maxn], is_leaf[maxn];
int tin[maxn], tout[maxn], timer, occ[2 * maxn];
ll depth[maxn];

void calc(int v, int par)
{
    occ[++ timer] = v;
    tin[v] = timer;
    sub[v] = 1;
    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);
        sub[v] += sub[u];
        occ[++ timer] = 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 <= (n - (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)];
}

int find_centroid(int v, int par, int sz)
{
    for (int u : adj[v])
    {
        if (u == par)
            continue;
 
        if (sub[u] > sz / 2)
        {
            return find_centroid(u, v, sz);
        }
    }
 
    return v;
}
 
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_leaves << " " << ans << endl; 

}
 
int used[maxn];
 
bool cmp(int v, int u)
{
    return tin[v] < tin[u];
}
void answer_queries()
{
    int root = 1;
    while(adj[root].size() == 1)
        root ++;
    calc(root, -1);
    build_sparse_table();

    find_depths(root);
    ll base = sum[root];
    for (int i = 1; i <= q; i ++)
    {
        int d;
        cin >> d;
        vector < int > nodes;
        for (int j = 1; j <= d; j ++)
        {
            int par;
            cin >> par;
            nodes.push_back(par);
        }
 
        if ((n <= 20000  && q <= 300) || q == 1)
        {
            for (int cur : nodes)
                added[cur] ++;
        
            find_depths(root);
            if (cnt[root] % 2 == 1)
                cout << -1 << endl;
            else
                cout << sum[root] << endl;
        }
        else
        {

            vector < int > attach;
            ll extra_ans = 0;
            for (int cur : nodes)
            {
                if (added[cur] == 0)
                {
                    extra_ans ++;
                }
                else
                {
                    attach.push_back(cur);
                }
                added[cur] ++;
            }
            sort(attach.begin(), attach.end(), cmp);
            
            if (attach.size() % 2 == 1)
                cout << -1 << endl;
            else
            {
                for (int i = 0; i < attach.size(); i += 2)
                {
                    extra_ans = extra_ans + get_distance(attach[i], attach[i + 1]) + 2;
                }
                cout << extra_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
 
3 1
1 2
1 3
6 3 3 3 2 2 2
 
*/

Compilation message (stderr)

cleaning.cpp: In function 'void answer_queries()':
cleaning.cpp:217:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  217 |                 for (int i = 0; i < attach.size(); i += 2)
      |                                 ~~^~~~~~~~~~~~~~~
cleaning.cpp:170:8: warning: unused variable 'base' [-Wunused-variable]
  170 |     ll base = sum[root];
      |        ^~~~

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