Submission #1114308

#	Time	Username	Problem	Language	Result	Execution time	Memory
1114308		Dan4Life	Synchronization (JOI13_synchronization)	C++17	0 / 100	81 ms	32608 KiB

synchronization

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define sz(a) (int)a.size()
#define all(a) begin(a),end(a)
using ar2 = array<int,2>;
const int N = (int)2e5+10;
int n, m, q;
vector<int> adj[N];
vector<ar2> edges;
set<int> S[N];
int st[N], dfs_timer;
int e[N], r[N], active[N];

void dfs(int s, int p){
	st[s] = dfs_timer++;
	for(auto u : adj[s]){
		if(u==p) continue;
		dfs(u,s);
	}
}

int dfs2(int s, int p, int curT){
	int ans = 1;
	for(auto u : adj[s]){
		if(u==p) continue;
		auto itr = S[u].upper_bound(curT);
		if(itr==begin(S[u])) continue;
		itr--; ans+=dfs2(u,s,*itr);
	}
	return ans;
}

int32_t main(){
	ios_base::sync_with_stdio(false); cin.tie(0);
	cin >> n >> m >> q;
	for(int i = 1; i < n; i++){
		int a, b; cin >> a >> b;
		adj[a].pb(b); adj[b].pb(a);
		edges.pb({a,b});
	}
	for(int i = 0; i < m; i++) cin >> e[i], e[i]--;
	for(int i = 0; i < q; i++) cin >> r[i], r[i]--;
	dfs(r[0],-1); S[r[0]].insert(m+1);
	for(int i = 0; i < m; i++){
		auto [a,b] = edges[e[i]];
		if(st[a]<st[b])swap(a,b);
		active[e[i]]^=1;
		if(!active[e[i]]) S[a].insert(i-1);
	}
	for(int i = 0; i < n-1; i++){
		auto [a,b] = edges[i];
		if(st[a]<st[b]) swap(a,b);
		if(active[i]) S[a].insert(m);
	}
	cout << dfs2(r[0],-1,*prev(end(S[r[0]]))) << "\n";
}

• Subtask 1: 0 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 10
• Subtask 4: 0 / 20
• Subtask 5: 0 / 40