Submission #232340

#	Time	Username	Problem	Language	Result	Execution time	Memory
232340		amoo_safar	Zagrade (COI17_zagrade)	C++14	100 / 100	663 ms	42224 KiB

zagrade

#include <bits/stdc++.h>

#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " : " << x << '\n'

using namespace std;

typedef long long ll;
typedef long double ld;
typedef string str;
typedef pair<ll, ll> pll;

const ll Mod = 1000000007LL;
const int N = 3e5 + 10;
const ll Inf = 2242545357980376863LL;
const ll Log = 30;

int n, a[N], mk[N];
vector<int> G[N];
ll ans = 0;

int sz[N];
int DFS(int u, int p){
	sz[u] = 1;
	for(auto adj : G[u])
		if(adj != p && !mk[adj])
			sz[u] += DFS(adj, u);
	return sz[u];
}
vector<int> V2, V3;
void DFS2(int u, int p, int sm, int mn){
	sm += a[u]; mn = min(mn, sm);
	if(sm == mn){
		if(mn == 0) ans ++;
		V2.pb(mn);
	}
	for(auto adj : G[u])
		if(adj != p && !mk[adj])
			DFS2(adj, u, sm, mn);
}
int tr;
void DFS3(int u, int p, int sm, int mn){
	sm -= a[u]; mn = min(mn, sm);
	if(sm == mn){
		if(tr && mn == -1) ans ++;
		V3.pb(mn);
	}
	for(auto adj : G[u])
		if(adj != p && !mk[adj])
			DFS3(adj, u, sm, mn);
}

int cnt2[N], cnt3[N];
void Centroid(int u){
	int m = DFS(u, -1);
	int fl = 1;
	int cen = u;
	while(fl){
		fl = 0;
		for(auto adj : G[cen]){
			if(!mk[adj] && sz[adj] < sz[cen] && sz[adj] + sz[adj] >= m){
				cen = adj;
				fl = 1;
				break;
			}
		}
	}
	//debug(cen);
	for(int i = 0; i <= m; i++) cnt2[i] = 0, cnt3[i] = 0;
	mk[cen] = 1;
	for(auto adj : G[cen]){
		if(mk[adj]) continue;
		V2.clear(); V3.clear();
		DFS2(adj, cen, a[cen], min(a[cen], 0));
		if(a[cen] == -1) tr = 1;
		else tr = 0;
		DFS3(adj, cen, 0, 0);
		for(auto &x : V2) ans += cnt3[-x];
		for(auto &x : V3) ans += cnt2[-x];
		
		for(auto &x : V2) cnt2[-x] ++;
		for(auto &x : V3) cnt3[-x] ++;
	}
	//debug(ans);
	for(auto adj : G[cen]){
		if(mk[adj]) continue;
		Centroid(adj);
	}

	return ;
}

int main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin >> n;
	char c;
	for(int i = 1; i <= n; i++){
		cin >> c;
		a[i] = (c == '(' ? 1 : -1);
	}
	int u, v;
	for(int i = 1; i < n; i++){
		cin >> u >> v;
		G[u].pb(v);
		G[v].pb(u);
	}
	Centroid(1);
	cout << ans << '\n';
	return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 60 / 60