Submission #770887

#	Time	Username	Problem	Language	Result	Execution time	Memory
770887		horiiseun	Railway (BOI17_railway)	C++17	100 / 100	92 ms	30360 KiB

railway

#include <iostream>
#include <vector>
#include <tuple>
#include <queue>
#include <stack>
#include <deque>
#include <set>
#include <map>
#include <cmath>
#include <random>
#include <string>
#include <cassert>
#include <climits>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>
using namespace std;

#define ll long long
#define f first
#define s second

void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
void __print(long long x) { cerr << x; }
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\'' << x << '\''; }
void __print(const char *x) { cerr << '\"' << x << '\"'; }
void __print(const string &x) { cerr << '\"' << x << '\"'; }
void __print(bool x) { cerr << (x ? "true" : "false"); }

template<typename A> void __print(const A &x);
template<typename A, typename B> void __print(const pair<A, B> &p);
template<typename... A> void __print(const tuple<A...> &t);
template<typename T> void __print(stack<T> s);
template<typename T> void __print(queue<T> q);
template<typename T, typename... U> void __print(priority_queue<T, U...> q);

template<typename A> void __print(const A &x) {
    bool first = true;
    cerr << '{';
    for (const auto &i : x) {
        cerr << (first ? "" : ","), __print(i);
        first = false;
    }
    cerr << '}';
}

template<typename A, typename B> void __print(const pair<A, B> &p) {
    cerr << '(';
    __print(p.f);
    cerr << ',';
    __print(p.s);
    cerr << ')';
}

template<typename... A> void __print(const tuple<A...> &t) {
    bool first = true;
    cerr << '(';
    apply([&first] (const auto &...args) { ((cerr << (first ? "" : ","), __print(args), first = false), ...); }, t);
    cerr << ')';
}

template<typename T> void __print(stack<T> s) {
    vector<T> debugVector;
    while (!s.empty()) {
        T t = s.top();
        debugVector.push_back(t);
        s.pop();
    }
    reverse(debugVector.begin(), debugVector.end());
    __print(debugVector);
}

template<typename T> void __print(queue<T> q) {
    vector<T> debugVector;
    while (!q.empty()) {
        T t = q.front();
        debugVector.push_back(t);
        q.pop();
    }
    __print(debugVector);
}

template<typename T, typename... U> void __print(priority_queue<T, U...> q) {
    vector<T> debugVector;
    while (!q.empty()) {
        T t = q.top();
        debugVector.push_back(t);
        q.pop();
    }
    __print(debugVector);
}

void _print() { cerr << "]\n"; }

template <typename Head, typename... Tail> void _print(const Head &H, const Tail &...T) {
    __print(H);
    if (sizeof...(T)) cerr << ", ";
    _print(T...);
}

#ifdef DEBUG
	#define D(...) cerr << "Line: " << __LINE__ << " [" << #__VA_ARGS__ << "] = ["; _print(__VA_ARGS__)
#else
	#define D(...)
#endif

int n, m, k, depth[100005], par[100005][20], in[100005], idx, val[100005];
map<pair<int, int>, int> id;
vector<int> adj[100005], ans;

void dfs1(int curr, int p) {
	in[curr] = idx++;
	for (int i : adj[curr]) {
		if (i == p) continue;
		depth[i] = depth[curr] + 1;
		par[i][0] = curr;
		dfs1(i, curr);
	}
}

int dfs2(int curr, int p) {
	for (int i : adj[curr]) {
		if (i == p) continue;
		val[curr] += dfs2(i, curr);
	}
	return val[curr];
}

int lca(int x, int y) {
	if (depth[x] < depth[y]) swap(x, y);
	for (int i = 19; i >= 0; i--) {
		if (depth[x] - depth[y] >= 1 << i) {
			x = par[x][i];
		}
	}
	if (x == y) return x;
	for (int i = 19; i >= 0; i--) {
		if (par[x][i] != par[y][i]) {
			x = par[x][i];
			y = par[y][i];
		}
	}
	return par[x][0];
}

int main() {

	ios_base::sync_with_stdio(false);
	cin.tie(0);

	cin >> n >> m >> k;
	for (int i = 0, a, b; i < n - 1; i++) {
		cin >> a >> b;
		id.insert({{min(a, b), max(a, b)}, i + 1});
		adj[a].push_back(b);
		adj[b].push_back(a);
	}

	dfs1(1, -1);

	for (int i = 1; i <= 19; i++) {
		for (int j = 1; j <= n; j++) {
			par[j][i] = par[par[j][i - 1]][i - 1];
		}
	}

	for (int i = 0, s; i < m; i++) {
		cin >> s;
		vector<int> v;
		for (int j = 0, x; j < s; j++) {
			cin >> x;
			v.push_back(x);
		}
		sort(v.begin(), v.end(), [](int a, int b) { return in[a] < in[b]; });
		for (int j = 0, l; j < s; j++) {
			l = lca(v[j], v[(j + 1) % s]);
			val[l] -= 2;
			val[v[j]]++;
			val[v[(j + 1) % s]]++;
		}
	}

	dfs2(1, -1);

	for (int i = 2; i <= n; i++) {
		if (val[i] >= 2 * k) {
			ans.push_back(id[{min(i, par[i][0]), max(i, par[i][0])}]);
		}
	}
	sort(ans.begin(), ans.end());

	cout << ans.size() << "\n";
	for (int i : ans) {
		cout << i << " ";
	}
	cout << "\n";

}

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