oj.uz

Submission #1043669

# Submission time Handle Problem Language Result Execution time Memory
1043669 2024-08-04T13:17:50 Z myst6 Spring cleaning (CEOI20_cleaning) C++14
70 / 100
 1000 ms 22096 KB 
#include <bits/stdc++.h>
 
using namespace std;
 
int main() {
    // take inputs
    cin.tie(0)->sync_with_stdio(0);
    int N, Q;
    cin >> N >> Q;
    vector<vector<int>> adj(2e5);
    for (int i=0; i<N-1; i++) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
 
    // analyse tree
    vector<int> parent(2e5, -1);
    vector<int> depth(2e5, 0);
    vector<int> parity(2e5, 0);
    vector<int> cost(2e5, 0);
    set<int> upd;
    auto dfs = [&](auto &self, int x) -> void {
        for (int y : adj[x]) {
            if (y != parent[x]) {
                parent[y] = x;
                depth[y] = depth[x] + 1;
                self(self, y);
                parity[x] ^= parity[y];
                cost[x] += cost[y] + 1;
                if (parity[y] == 0) cost[x] += 1;
            }
        }
        if (adj[x].size() == 1) parity[x] ^= 1;
    };
    dfs(dfs, 0);
 
    // check for subtask 6
    bool subtask_6 = true;
    vector<vector<int>> queries(Q);
    for (int i=0; i<Q; i++) {
        int D;
        cin >> D;
        if (D != 1) subtask_6 = false;
        for (int j=0; j<D; j++) {
            int a;
            cin >> a;
            queries[i].push_back(a);
        }
    }
 
    if (subtask_6) {
        vector<int> n_odd(N), n_even(N);
        auto dfs = [&](auto &self, int x) -> void {
            if (parity[x] == 1) n_odd[x] += 1;
            if (parity[x] == 0) n_even[x] += 1;
            for (int y : adj[x]) {
                if (y != parent[x]) {
                    n_odd[y] += n_odd[x];
                    n_even[y] += n_even[x];
                    self(self, y);
                }
            }
        };
        dfs(dfs, 0);
        for (int i=0; i<Q; i++) {
            int x = queries[i][0];
            x--;
            if (adj[x].size() == 1) {
                if (parity[0] == 1) {
                    cout << "-1\n";
                } else {
                    cout << cost[0] + 1 << "\n";
                }
            } else {
                if (parity[0] == 0) {
                    cout << "-1\n";
                } else {
                    cout << cost[0] + n_odd[x] - n_even[x] << "\n";
                }
            }
        }
        return 0;
    }
 
    // handle queries
    for (int i=0; i<Q; i++) {
        set<pair<int,int>> upd;
        for (int j=0; j<queries[i].size(); j++) {
            int a = queries[i][j];
            a--;
            adj[a].push_back(N + j);
            parity[N + j] = 1;
            cost[N + j] = 0;
            upd.insert({depth[a], a});
        }
        set<pair<int,int>> upd_copy(upd);
        while (!upd.empty()) {
            auto it = prev(upd.end());
            int d = it->first, x = it->second;
            upd.erase(it);
            if (x == -1) continue;
            parity[x] = 0;
            cost[x] = 0;
            for (int y : adj[x]) {
                if (y != parent[x]) {
                    parity[x] ^= parity[y];
                    cost[x] += cost[y] + 1;
                    if (parity[y] == 0) cost[x] += 1;
                }
            }
            if (adj[x].size() == 1) parity[x] ^= 1;
            upd.insert({d - 1, parent[x]});
        }
        // if the root of the tree has odd parity, it is impossible to clean, otherwise output its cost
        if (parity[0] == 1) {
            cout << "-1\n";
        } else {
            cout << cost[0] << "\n";
        }
        if (i == Q - 1) continue; // no need to reverse changes on last query
        // reverse changes
        while (!upd_copy.empty()) {
            auto it = prev(upd_copy.end());
            int d = it->first, x = it->second;
            upd_copy.erase(it);
            if (x == -1) continue;
            while (adj[x].back() >= N) adj[x].pop_back();
            parity[x] = 0;
            cost[x] = 0;
            for (int y : adj[x]) {
                if (y != parent[x]) {
                    parity[x] ^= parity[y];
                    cost[x] += cost[y] + 1;
                    if (parity[y] == 0) cost[x] += 1;
                }
            }
            if (adj[x].size() == 1) parity[x] ^= 1;
            upd_copy.insert({d - 1, parent[x]});
        }
    }
 
    return 0;
}

Compilation message

cleaning.cpp: In function 'int main()':
cleaning.cpp:91:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   91 |         for (int j=0; j<queries[i].size(); j++) {
      |                       ~^~~~~~~~~~~~~~~~~~

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8280 KB Output is correct
2 Correct 131 ms 10076 KB Output is correct

Subtask #2
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 9172 KB Output is correct
2 Correct 15 ms 9176 KB Output is correct
3 Correct 17 ms 12260 KB Output is correct
4 Correct 40 ms 15852 KB Output is correct
5 Correct 53 ms 17772 KB Output is correct

Subtask #3
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 9948 KB Output is correct
2 Correct 16 ms 9944 KB Output is correct
3 Correct 27 ms 16648 KB Output is correct
4 Correct 52 ms 21508 KB Output is correct
5 Correct 24 ms 15704 KB Output is correct

Subtask #4
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 398 ms 10068 KB Output is correct
2 Correct 48 ms 9308 KB Output is correct
3 Correct 6 ms 9048 KB Output is correct
4 Correct 7 ms 9308 KB Output is correct
5 Correct 356 ms 9308 KB Output is correct
6 Correct 406 ms 9808 KB Output is correct

Subtask #5
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 14828 KB Output is correct
2 Correct 201 ms 12708 KB Output is correct
3 Correct 156 ms 11348 KB Output is correct
4 Correct 208 ms 12884 KB Output is correct
5 Correct 196 ms 12708 KB Output is correct

Subtask #6
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 18768 KB Output is correct
2 Correct 51 ms 21844 KB Output is correct
3 Correct 43 ms 21504 KB Output is correct
4 Correct 44 ms 22096 KB Output is correct

Subtask #7
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8280 KB Output is correct
2 Correct 131 ms 10076 KB Output is correct
3 Correct 14 ms 9172 KB Output is correct
4 Correct 15 ms 9176 KB Output is correct
5 Correct 17 ms 12260 KB Output is correct
6 Correct 40 ms 15852 KB Output is correct
7 Correct 53 ms 17772 KB Output is correct
8 Correct 16 ms 9948 KB Output is correct
9 Correct 16 ms 9944 KB Output is correct
10 Correct 27 ms 16648 KB Output is correct
11 Correct 52 ms 21508 KB Output is correct
12 Correct 24 ms 15704 KB Output is correct
13 Correct 398 ms 10068 KB Output is correct
14 Correct 48 ms 9308 KB Output is correct
15 Correct 6 ms 9048 KB Output is correct
16 Correct 7 ms 9308 KB Output is correct
17 Correct 356 ms 9308 KB Output is correct
18 Correct 406 ms 9808 KB Output is correct
19 Correct 25 ms 14828 KB Output is correct
20 Correct 201 ms 12708 KB Output is correct
21 Correct 156 ms 11348 KB Output is correct
22 Correct 208 ms 12884 KB Output is correct
23 Correct 196 ms 12708 KB Output is correct
24 Correct 38 ms 18768 KB Output is correct
25 Correct 51 ms 21844 KB Output is correct
26 Correct 43 ms 21504 KB Output is correct
27 Correct 44 ms 22096 KB Output is correct
28 Correct 195 ms 12880 KB Output is correct
29 Execution timed out 1043 ms 15436 KB Time limit exceeded
30 Halted 0 ms 0 KB -