Submission #379740

#	Time	Username	Problem	Language	Result	Execution time	Memory
379740		cgiosy	Mergers (JOI19_mergers)	C++17	0 / 100	84 ms	12900 KiB

mergers

#include <bits/stdc++.h>
using namespace std;

int main() {
	ios::sync_with_stdio(0);cin.tie(0);
	int N, M, ans=1;
	cin>>N>>M;
	vector<int> C(N), D(N), P(N, -1);
	vector<vector<int>> G(N), H(M);
	for(int i=1; i<N; i++) {
		int x, y;
		cin>>x>>y; --x, --y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
	for(int i=0; i<N; i++) cin>>C[i], H[--C[i]].push_back(i);
	function<int(int)> root=[&](int i) { return P[i]>=0 ? P[i]=root(P[i]) : i; };
	function<void(int, int)> dep=[&](int i, int p) {
		for(int j:G[i]) if(j!=p) D[j]=D[i]+1, dep(j, i);
	};
	function<int(int, int)> dfs=[&](int i, int p) {
		int cnt=1;
		for(int j:G[i]) if(j!=p) {
			int v=dfs(j, i);
			cnt=~cnt && ~v ? cnt+v : -1;
		}
		p=i;
		for(int q:H[C[i]]) {
			p=root(p), q=root(q);
			if(p==q) continue;
			if(D[p]>D[q]) swap(p, q);
			P[p]+=P[q], P[q]=p;
		}
		H[C[i]].clear();
		if(~cnt && i==p && -P[i]==cnt) ans++, cnt=-1;
		return cnt;
	};
	dep(0, 0);
	dfs(0, 0);
	cout<<ans/2<<'\n';
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 24
• Subtask 3: 0 / 14
• Subtask 4: 0 / 22
• Subtask 5: 0 / 30