Submission #838784

#	Time	Username	Problem	Language	Result	Execution time	Memory
838784		sysia	Prize (CEOI22_prize)	C++17	0 / 100	3441 ms	439344 KiB

Main

//Sylwia Sapkowska
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

void __print(int x) {cerr << x;}
void __print(long long 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 T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef LOCAL
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

void ckmin(int &a, int b) {a = min(a, b);}
typedef pair<int, int> T;
const int oo2 = 1e9+7;
const int K = 20;

vector<bool>active;

struct graph{
	vector<vector<T>>g;
	vector<vector<int>>up;
	vector<int>depth, deg, par, pre, post;
	int n, root, tt = 0;
	vector<T>edges;

	graph(int nn){
		n = nn;
		g.resize(n+1);
		deg.resize(n+1);
		pre.resize(n+1);
		post.resize(n+1);
		par.assign(n+1, -1);
		depth.assign(n+1, 0);
		up.resize(n+1, vector<int>(K));
		for (int i = 1; i<=n; i++){
			int p; cin >> p;
			if (p == -1) root = i;
			else {
				par[i] = p;
				g[p].emplace_back(i, 0);
			}
		}
		for (int i = 1; i<=n; i++) deg[i] = (int)g[i].size();
		dfs(root, root);
	}

	void dfs(int v, int pa){
		pre[v] = ++tt;
		up[v][0] = pa;
		for (int i = 1; i<K; i++) up[v][i] = up[up[v][i-1]][i-1];
		for (auto [x, __]: g[v]){
			if (x == pa) continue;
			dfs(x, v);
		}
		post[v] = ++tt;
	}

	int lca(int a, int b){
		if (!subtree(a, b)) swap(a, b);
		for (int i = K-1; i>=0; i--){
			if (subtree(a, b)){
				b = up[b][i];
			}
		}
		if (a == b) return a;
		for (int i = K-1; i>=0; i--){
			if (up[a][i] != up[b][i]){
				a = up[a][i];
				b = up[b][i];
			}
		}
		return up[a][0];
	}

	void remove(int v){
		int p = par[v];
		if (p == -1) return;
		if ((int)deg[v] == 0){ //lisc
			deg[p]--;
		} else { //z pionowej sciezki ---> jest tylko jedno dziecko,podlaczyc do rodzica v
			while (!active[g[v].back().first]) g[v].pop_back();
			assert(!g[v].empty());
			auto x = g[v].back().first;
			g[p].emplace_back(x, 0);
			par[x] = p;
		}
	}

	bool subtree(int a, int b){ //czy b w poddrzewie a
		return (pre[a] <= pre[b] && post[a] >= post[b]);
	}

	void make_vt(vector<int>curr){
		stable_sort(curr.begin(), curr.end(), [&](auto x, auto y){
			return pre[x] < pre[y];
		});
		for (int i = 1; i<=n; i++) g[i].clear();
		vector<int>s = {curr[0]};
		for (int i = 1; i<(int)curr.size(); i++){
			while (!subtree(s.back(), curr[i])){
				//czyli curr[i] poza poddrzewem
				s.pop_back();
			} 			
			assert(!s.empty());
			edges.emplace_back(curr[i], s.back());
			s.emplace_back(curr[i]);
		}
		debug(edges);
		root = curr[0];
	}

	void bfs(){
		queue<int>q;
		q.push(root);
		vector<bool>vis(n+1);
		vis[root] = 1;
		while ((int)q.size()){
			int v = q.front(); q.pop();
			for (auto [x, c]: g[v]){
				if (!vis[x]){
					depth[x] = depth[v]+c;
					vis[x] = 1;
					q.push(x);
				}
			}
		}
		for (int i = 1; i<=n; i++){
			if (active[i]){
				debug(i, depth[i]);
			}
		}
	}

	int get_dist(int a, int b){
		return depth[a] + depth[b] - 2 * depth[lca(a, b)];
	}

	void add(int a, int l, int c){
		if (c) {
			g[a].emplace_back(l, c);
			g[l].emplace_back(a, c);
		}
	}
};

void solve(){
	int n, k, q, t; cin >> n >> k >> q >> t;
	graph g1(n), g2(n);
	active.assign(n+1, 1);
	stack<int>s;
	auto cute = [&](int v){
		return g1.deg[v] <= 1 && g2.deg[v] <= 1 && active[v];
	};
	for (int i = 1; i<=n; i++) if (cute(i)) s.push(i);
	for (int rep = 0; rep<n-k; rep++){
		while ((int)s.size() && !active[s.top()]) s.pop();
		assert(!s.empty());
		int v = s.top(); s.pop();
		debug(v);
		active[v] = 0;
		g1.remove(v);
		g2.remove(v);
		for (auto ck: {g1.par[v], g2.par[v]}){
			if (ck != -1 && cute(ck)) {
				s.push(ck);
			}
		}
	}
	vector<int>curr;
	for (int i = 1; i<=n; i++) if (active[i]) curr.emplace_back(i);
	for (auto u: curr) cout << u << " ";
	cout << "\n"; cout.flush();	
	g1.make_vt(curr);
	g2.make_vt(curr);
	for (auto [a, b]: g1.edges){
		cout << "? " << a << " " << b << "\n";
	}
	cout << "!\n"; cout.flush();
	for (auto [a, b]: g1.edges){
		int a1, b1, a2, b2; cin >> a1 >> b1 >> a2 >> b2;
		//b w poddrzewie a
		assert(b1 == 0);
		g1.add(a, b, a1); //a, lca, w
		int lca = g2.lca(a, b);
		g2.add(a, lca, a2);
		g2.add(b, lca, b2);
	}
	g1.bfs();
	g2.bfs();
	vector<T>que;
	while (t--){
		int a, b; cin >> a >> b;
		que.emplace_back(a, b);
	}
	for (auto [a, b]: que){
		int l = g1.lca(a, b);
		cout << g1.get_dist(a, b) << " " << g2.get_dist(a, b) << "\n";
	}
	cout.flush();
}

int32_t main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);

	solve();
	
	return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void solve()':
Main.cpp:211:7: warning: unused variable 'l' [-Wunused-variable]
  211 |   int l = g1.lca(a, b);
      |       ^

• Subtask 1: 0 / 10
• Subtask 2: 0 / 25
• Subtask 3: 0 / 19
• Subtask 4: 0 / 22
• Subtask 5: 0 / 24