oj.uz

Submission #961340

# Submission time Handle Problem Language Result Execution time Memory
961340 2024-04-11T21:21:42 Z biank Railway (BOI17_railway) C++14
36 / 100
 55 ms 24880 KB 
#include <bits/stdc++.h>
 
using namespace std;
 
#define all(x) begin(x), end(x)
 
using ii = pair<int, int>; 

const int MAX_N = 1e5 + 9;
const int MAX_K = 18;
 
vector<ii> adj[MAX_N];
int up[MAX_K][MAX_N], d[MAX_N];
int in[MAX_N], t = 0;
int idx[MAX_N];
 
void dfs(int u, int p = 0, int h = 0) {
    in[u] = t++, up[0][u] = p, d[u] = h;
    for (auto [v, i] : adj[u]) {
        if (v != p) {
            idx[v] = i;
            dfs(v, u, h + 1);
        }
    }
}
 
void init(int n) {
    for (int i = 0; i < MAX_K - 1; i++) {
        for (int j = 1; j <= n; j++) {
            up[i + 1][j] = up[i][up[i][j]];
        }
    }
}
 
int lca(int a, int b) {
    if (d[a] < d[b]) {
        swap(a, b);
    }
    int diff = d[a] - d[b];
    for (int i = 0; i < MAX_K; i++) {
        if (diff >> i & 1) a = up[i][a];
    }
    if (a == b) {
        return a;
    }
    for (int i = MAX_K - 1; i >= 0; i--) {
        if (up[i][a] != up[i][b]) {
            a = up[i][a];
            b = up[i][b];
        }
    }
    return up[0][a];
}
 
int ans[MAX_N], c = 0, k;
 
void dfs2(int u, int p = 0) {
    for (auto [v, i] : adj[u]) {
        if (v != p) {
            dfs2(v, u);
            ans[u] += ans[v];
        }
    }
    if (ans[u] >= 2 * k) c++;
}
 
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    
    int n, m;
    cin >> n >> m >> k;
    for (int i = 1; i < n; i++) {
        int a, b;
        cin >> a >> b;
        adj[a].emplace_back(b, i);
        adj[b].emplace_back(a, i);
    }
    dfs(1);
    init(n);
    for (int i = 0; i < m; i++) {
        int s;
        cin >> s;
        vector<int> a(s);
        for (int j = 0; j < s; j++) {
            cin >> a[j];
        }
        sort(all(a), [&](const int &x, const int &y) {
            return in[x] < in[y];
        });
        auto nxt = [&s](int j) {
            if (++j == s) j = 0;
            return j;
        };
        for (int j = 0; j < s; j++) {
            int x = a[j];
            int y = a[nxt(j)];
            ++ans[x], ++ans[y];
            ans[lca(x, y)] -= 2;
        }
    }
    dfs2(1);
    cout << c << '\n';
    for (int i = 2; i <= n; i++) {
        if (ans[i] >= 2 * k) cout << idx[i] << ' ';
    }
   
    
    return 0;
}

Compilation message

railway.cpp: In function 'void dfs(int, int, int)':
railway.cpp:19:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   19 |     for (auto [v, i] : adj[u]) {
      |               ^
railway.cpp: In function 'void dfs2(int, int)':
railway.cpp:58:15: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   58 |     for (auto [v, i] : adj[u]) {
      |               ^

Subtask #1
0 / 8.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 9052 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #2
0 / 15.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 9052 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 51 ms 24480 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Correct 55 ms 24656 KB Output is correct
4 Correct 46 ms 24148 KB Output is correct
5 Correct 49 ms 24400 KB Output is correct
6 Correct 49 ms 24880 KB Output is correct

Subtask #4
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 42 ms 20508 KB Output is correct
2 Correct 49 ms 17236 KB Output is correct
3 Correct 46 ms 16912 KB Output is correct
4 Correct 48 ms 16724 KB Output is correct
5 Correct 50 ms 16924 KB Output is correct
6 Correct 43 ms 20560 KB Output is correct
7 Correct 55 ms 20752 KB Output is correct

Subtask #5
0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 42 ms 20508 KB Output is correct
2 Correct 49 ms 17236 KB Output is correct
3 Correct 46 ms 16912 KB Output is correct
4 Correct 48 ms 16724 KB Output is correct
5 Correct 50 ms 16924 KB Output is correct
6 Correct 43 ms 20560 KB Output is correct
7 Correct 55 ms 20752 KB Output is correct
8 Correct 47 ms 20684 KB Output is correct
9 Correct 45 ms 20600 KB Output is correct
10 Correct 48 ms 24660 KB Output is correct
11 Correct 45 ms 24456 KB Output is correct
12 Incorrect 36 ms 16472 KB Output isn't correct
13 Halted 0 ms 0 KB -

Subtask #6
0 / 25.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 9052 KB Output isn't correct
2 Halted 0 ms 0 KB -