oj.uz

Submission #834417

# Submission time Handle Problem Language Result Execution time Memory
834417 2023-08-22T14:05:51 Z NK_ Mergers (JOI19_mergers) C++17
0 / 100
 111 ms 21228 KB 
// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
 
using namespace std;
 
#define nl '\n'
#define pb push_back
#define pf push_front
 
#define mp make_pair
#define f first
#define s second
#define sz(x) int(x.size())
 
template<class T> using V = vector<T>;
using pi = pair<int, int>;
using vi = V<int>;
using vpi = V<pi>;
 
using ll = long long;
using pl = pair<ll, ll>;
using vpl = V<pl>;
using vl = V<ll>;
 
using db = long double;
 
template<class T> using pq = priority_queue<T, V<T>, less<T>>;
 
const int MOD = 1e9 + 7;
const ll INFL = ll(1e17);
const int LG = 19;

int main() {
	cin.tie(0)->sync_with_stdio(0);
  	
	int N, K; cin >> N >> K;

	V<vi> adj(N); for(int i = 0; i < N - 1; i++) {
		int u, v; cin >> u >> v; --u, --v;
		adj[u].pb(v);
		adj[v].pb(u);
	}

	vi A(N); for(auto& x : A) { cin >> x; --x; }

	int R = -1; for(int i = 0; i < N; i++) if (sz(adj[i]) >= 2) R = i;

	if (R == -1) {
		if (N == 1) cout << 0 << nl;
		else {
			if (A.front() == A.back()) cout << 0 << nl;
			else cout << 1 << nl;
		}
		exit(0-0);
	}

	V<vi> up(N, vi(LG)); vi dep(N);
	function<void(int, int)> gen = [&](int u, int p) {
		up[u][0] = p; dep[u] = (u == p ? 0 : dep[p] + 1);
		for(int i = 1; i < LG; i++) up[u][i] = up[up[u][i-1]][i-1];

		for(auto& v : adj[u]) if (v != p) gen(v, u);
	};
	
	auto jmp = [&](int u, int d) {
		for(int i = 0; i < LG; i++) if ((d >> i) & 1) u = up[u][i];
		return u;
	};

	auto lca = [&](int a, int b) {
		if (dep[a] < dep[b]) swap(a, b);
		a = jmp(a, dep[a] - dep[b]);
		if (a == b) return a;

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

	gen(R, R);

	vi L(K, -1); for(int u = 0; u < N; u++) {
		if (L[A[u]] == -1) L[A[u]] = u;
		else L[A[u]] = lca(L[A[u]], u);
	}

	// cerr << "R: " << R << endl;

	int ans = 0, all = 0; vi U(N);
	function<int(int, int)> dfs = [&](int u, int p) {
		int amt = 0; U[u] = L[A[u]];
		for(auto& v : adj[u]) if (v != p) {
			amt += dfs(v, u);
			U[u] = lca(U[u], U[v]);
		}

		if (U[u] == u) {
		 	if (amt == 0) amt++;
		 	all++;
		 }


		int take = (amt % 2 ? 1 : 2);
		amt -= take; ans += amt / 2;
		return take;
	};

	ans += (dfs(R, R) + 1) / 2;


	if (all == 1) cout << 0 << nl;
	else cout << ans << nl;

    return 0;	
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 1 ms 340 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 1 ms 340 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 1 ms 340 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 65 ms 19224 KB Output is correct
2 Correct 111 ms 21228 KB Output is correct
3 Incorrect 3 ms 852 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 1 ms 340 KB Output isn't correct
3 Halted 0 ms 0 KB -