Submission #927777

#	Time	Username	Problem	Language	Result	Execution time	Memory
927777		Amirreza_Fakhri	Railway (BOI17_railway)	C++17	100 / 100	196 ms	41812 KiB

railway

// In the name of the God
#include <bits/stdc++.h>
#define ll long long
// #define int long long
#define pb push_back
#define F first
#define S second
#define mp make_pair
#define pii pair <int, int>
#define smin(x, y) (x) = min((x), (y))
#define smax(x, y) (x) = max((x), (y))
#define all(x) (x).begin(), (x).end()
using namespace std;

const int inf = 1e9+7;
const int mod = 998244353;
const int maxn = 1e5+5;

int n, m, k, s[maxn], res[maxn], sz[maxn];
vector <pii> adj[maxn];
vector <int> col[maxn], ans;
map <int, int> cnt[maxn];

void relax(int v, int c, int x) {
    if (cnt[v][c] == 0) res[v]++;
    cnt[v][c] += x;
    if (cnt[v][c] == s[c]) res[v]--;
}

void dfs(int v, int p, int ed) {
    for (int c : col[v]) relax(v, c, 1);
    sz[v] = col[v].size();
    for (pii e : adj[v]) {
        int u = e.F;
        if (u == p) continue;
        dfs(u, v, e.S);
        if (sz[u] > sz[v]) {
            res[v] = res[u];
            swap(cnt[v], cnt[u]);
        }
        for (auto it = cnt[u].begin(); it != cnt[u].end(); it++) relax(v, it->F, it->S);
        sz[v] += sz[u];
    }
    if (res[v] >= k) ans.pb(ed);
}  

int32_t main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n >> m >> k;
    for (int i = 1; i < n; i++) {
        int v, u; cin >> v >> u;
        adj[--v].pb(mp(--u, i));
        adj[u].pb(mp(v, i));
    }
    for (int i = 0; i < m; i++) {
        cin >> s[i];
        for (int j = 0; j < s[i]; j++) {
            int v; cin >> v;
            col[--v].pb(i);
        }
    }
    dfs(0, 0, 0);
    sort(all(ans));
    cout << ans.size() << '\n';
    for (int i : ans) cout << i << ' ';
    cout << '\n';
    return 0;
}

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 16 / 16
• Subtask 6: 25 / 25