Submission #1271438

#	Time	Username	Problem	Language	Result	Execution time	Memory
1271438		red_souls	Spring cleaning (CEOI20_cleaning)	C++20	16 / 100	1096 ms	6476 KiB

cleaning

#include <bits/stdc++.h>
#define ll long long
#define task "crt"
using namespace std;

const int N = 1e5 + 16;
int n, q, u, v, a[N];
vector <int> adj[N];
ll result;

/*
7 3
1 2
2 4
4 5
5 6
5 7
3 4
1 4
2 2 4
1 1
*/

void deleteEdge(int u, int v) {
    for (int i = 0; i < adj[u].size(); i++) {
        if (adj[u][i] == v) {
            adj[u].erase(adj[u].begin() + i);
            break;
        }
    }
    for (int i = 0; i < adj[v].size(); i++) {
        if (adj[v][i] == u) {
            adj[v].erase(adj[v].begin() + i);
            break;
        }
    }
}

int leaves[N];

void preDfs(int k, int p) {
    if (adj[k].size() == 1) {
        leaves[k] = 1;
    }
    else {
        leaves[k] = 0;
    }
    for (auto v : adj[k]) {
        if (v == p) {
            continue;
        }
        preDfs(v, k);
        leaves[k] += leaves[v];
    }
}

int main() {
    ios_base :: sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }

    cin >> n >> q;
    for (int i = 1; i < n; i++) {
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    while (q--) {
        int d;
        cin >> d;
        for (int i = 1; i <= d; i++) {
            cin >> a[i];
        }




        for (int i = 1; i <= d; i++) {
            adj[n + i].push_back(a[i]);
            adj[a[i]].push_back(n + i);
        }

        preDfs(1, 1);
        if (leaves[1] & 1) {
            result = -1;
        }
        else {
            result = 0;
            for (int i = 2; i <= n + d; i++) {
                if (leaves[i] & 1) {
                    result++;
                }
                else {
                    result += 2;
                }
            }
        }
        cout << result << "\n";

        for (int i = 1; i <= d; i++) {
            deleteEdge(n + i, a[i]);
        }
    }

    return 0;
}

Compilation message (stderr)

cleaning.cpp: In function 'int main()':
cleaning.cpp:63:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
cleaning.cpp:64:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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