Submission #417470

#	Time	Username	Problem	Language	Result	Execution time	Memory
417470		shivensinha4	Mergers (JOI19_mergers)	C++17	100 / 100	1295 ms	152372 KiB

mergers

#include <bits/stdc++.h>
#ifdef mlocal
#include "./Competitive-Code-Library/snippets/prettyprint.h"
#endif
using namespace std;
#define for_(i, s, e) for (int i = s; i < (int) e; i++)
#define for__(i, s, e) for (ll i = s; i < e; i++)
typedef long long ll;
typedef vector<int> vi;
typedef array<int, 2> ii;
#define endl '\n'

int main() {
#ifdef mlocal
	freopen("test.in", "r", stdin);
#endif
	
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	int n, k; cin >> n >> k;
	vector<vi> adj(n);
	for_(i, 0, n-1) {
		int a, b; cin >> a >> b;
		a -= 1; b -= 1;
		adj[a].push_back(b); adj[b].push_back(a);
	}
	vi st(n), ct(n);
	for_(i, 0, n) {
		cin >> st[i];
		st[i] -= 1;
		ct[st[i]]++;
	}
	
	vector<map<int, int>> mp(n);
	vi deg(n);
	
	function<void(int,int)> dfs = [&](int p, int parent) {
		if (ct[st[p]] != 1) mp[p][st[p]] = 1;
		
		for (auto i: adj[p]) if (i != parent) {
			dfs(i, p);
			if (!mp[i].size()) {
				deg[p]++;
				deg[i]++;
			}
			else {
				deg[p] += deg[i];
				deg[i] = 0;
			}
			
			if (mp[i].size() > mp[p].size()) mp[p].swap(mp[i]);
			vi rem;
			for (auto &v: mp[i]) {
				mp[p][v.first] += v.second;
				if (mp[p][v.first] == ct[v.first]) rem.push_back(v.first);
			}
			
			for (auto v: rem) mp[p].erase(v);
		}
	};
	
	dfs(0, 0);
	int odd = 0;
	for_(i, 0, n) if (deg[i] == 1) odd++;
	cout << (odd+1)/2 << endl;
}

• Subtask 1: 10 / 10
• Subtask 2: 24 / 24
• Subtask 3: 14 / 14
• Subtask 4: 22 / 22
• Subtask 5: 30 / 30