Submission #887527

#	Time	Username	Problem	Language	Result	Execution time	Memory
887527		AgentPengin	Synchronization (JOI13_synchronization)	C++17	100 / 100	224 ms	25356 KiB

synchronization

/**
 *    author:  AgentPengin ( Độc cô cầu bại )
 *    created: 23.12.2022 10:08:02
 *    too lazy to update time
**/
#include<bits/stdc++.h>

#define EL '\n'
#define fi first
#define se second
#define NAME "TASK"
#define ll long long
#define lcm(a,b) (a/gcd(a,b))*b
#define db(val) "["#val" = " << (val) << "] "
#define bend(v) (v).begin(),(v).end()
#define sz(v) (int)(v).size()
#define ex exit(0)

using namespace std;

const ll mod = 1e9 + 7;
const int inf = 0x1FFFFFFF;
const int MAXN = 1e5 + 5;

int n,m,q;
vector<int> adj[MAXN];
pair<int,int> edges[MAXN << 1];
bool active[MAXN];

int info[MAXN],last_sync[MAXN];

int times = 1,tin[MAXN],tout[MAXN];
int up[MAXN][20];

void dfs(int u = 1,int p = 0) {
	up[u][0] = p;
	for (int i = 1;i < 20 && up[u][i - 1];i++) {
		up[u][i] = up[up[u][i - 1]][i - 1];
	}
	info[u] = 1;
	tin[u] = times++;
	for (auto v : adj[u]) if (v != p) dfs(v,u);
	tout[u] = times;
}

int bit[MAXN];

void update(int x,int val) {
	for (;x <= n;x += x&-x) bit[x] += val;
}

int get(int x) {
	int res = 0;
	for (;x;x-=x&-x) res += bit[x];
	return res;
}

int find_anc(int u) {
	int lca = u;
	for (int i = 19; ~ i;i--) {
		if (up[lca][i] && get(tin[up[lca][i]]) == get(tin[u])) lca = up[lca][i];
	}
	return lca;
}

signed main() {
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    if (ifstream(NAME".inp")) {
        freopen(NAME".inp","r",stdin);
        freopen(NAME".out","w",stdout);
    }
    cin >> n >> m >> q;
    for (int i = 1;i < n;i++) {
    	cin >> edges[i].fi >> edges[i].se;
    	adj[edges[i].fi].push_back(edges[i].se);
    	adj[edges[i].se].push_back(edges[i].fi);
    }
    dfs();
    for (int i = 1;i <= n;i++) {
    	update(tin[i],-1);
    	update(tout[i],1);
    }
    while(m--) {
    	int x; cin >> x;
    	int u = edges[x].fi,v = edges[x].se;
    	if (up[u][0] == v) swap(u,v);
    	if (active[x]) {
    		info[v] = last_sync[v] = info[find_anc(u)];
    		update(tin[v],-1);
    		update(tout[v],1);
    	} else {
    		info[find_anc(u)] += info[v] - last_sync[v];
    		update(tin[v],1);
    		update(tout[v],-1);
    	}
    	active[x] = !active[x];
    }
	while(q--) {
		int x;
		cin >> x;
		cout << info[find_anc(x)] << EL;
	}
    cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
    return 0;
}
// agent pengin wants to take apio (with anya-san)

Compilation message (stderr)

synchronization.cpp: In function 'int main()':
synchronization.cpp:69:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |         freopen(NAME".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:70:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |         freopen(NAME".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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