Submission #1264647

#	Time	Username	Problem	Language	Result	Execution time	Memory
1264647		tminh	Synchronization (JOI13_synchronization)	C++20	100 / 100	170 ms	22724 KiB

synchronization

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

#define task ""
#define ll long long
#define endl '\n'
#define u first
#define v second
#define vall(a) (a).begin(), (a).end()
#define sze(a) (int)a.size()
#define pii pair<int, int>
#define pll pair<ll, ll>


#define ep emplace_back
#define pb push_back
#define pf push_front


const ll mod = 1e9 + 7;
const int N = 1e5 + 5;
const ll oo = 1e18;

bool START;

int n, m, q, in[N], out[N], par[N][19], t = 0;
pii e[N];
bool vis[N];
vector<int> adj[N];

// so lan doc sol roi moi biet lam : 4 / 4

struct BIT {
	int bit[N];
	void add(int idx, int delta) {
		for (; idx <= n; idx += idx & -idx) bit[idx] += delta;
	}
	void upd(int l, int r, int delta) {
		add(l, delta);
		add(r + 1, -delta);
	}
	int get(int idx) {
		int ans = 0;
		for (; idx > 0; idx -= idx & -idx) ans += bit[idx];
		return ans;
	}
} bit;

void dfs(int u, int p) {
	in[u] = ++t;
	for (int v : adj[u]) {
		if (v == par[u][0]) continue;
		par[v][0] = u;
		for (int i = 1; i < 19; ++i) par[v][i] = par[par[v][i - 1]][i - 1]; 
		dfs(v, u);
	}
	out[u] = t;
}

int find(int u) {
	for (int i = 18; i >= 0; --i) if (bit.get(in[par[u][i]]) == bit.get(in[u])) u = par[u][i];
	return u;
}


int ans[N], lst[N];
inline void solve() {
	dfs(1, 0);
	for (int i = 1; i <= n; ++i) {
		ans[i] = 1;
		bit.upd(in[i], out[i], 1);
	}
	for (int i = 1; i <= m; ++i) {
		int x; cin >> x;
		auto[u, v] = e[x];
		if (par[v][0] != u) swap(u, v);
		
		if (!vis[x]) {
			ans[find(u)] += ans[v] - lst[v];
			bit.upd(in[v], out[v], -1);
		} else {
			ans[v] = lst[v] = ans[find(u)];
			bit.upd(in[v], out[v], 1);
		}
		vis[x] ^= 1;
	}
	while(q--) {
		int x; cin >> x;
		cout << ans[find(x)] << endl;
	}
}


inline void input() {
    cin >> n >> m >> q;
    for (int i = 1; i < n; ++i) {
    	cin >> e[i].u >> e[i].v;
    	adj[e[i].u].pb(e[i].v);
    	adj[e[i].v].pb(e[i].u);
    }
    return solve();
}
bool END;

int main() {
    if(fopen(task ".inp", "r")) {
        freopen(task ".inp", "r", stdin);
        freopen(task ".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);

    input();
    
    
    cerr << endl << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << 's' << endl;
    cerr << "Memory: " << fabs ((&END - &START)) / 1048576.0 << "MB\n";
    return 0;
}

Compilation message (stderr)

synchronization.cpp: In function 'int main()':
synchronization.cpp:107:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  107 |         freopen(task ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:108:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  108 |         freopen(task ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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