Submission #91756

#	Time	Username	Problem	Language	Result	Execution time	Memory
91756		jasony123123	Zagrade (COI17_zagrade)	C++11	100 / 100	1417 ms	78892 KiB

zagrade

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include <ext/pb_ds/tree_policy.hpp>
//#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
//using namespace __gnu_pbds;

#define FOR(i,start,end) for(int i=start;i<(int)(end);i++)
#define FORE(i,start,end) for(int i=start;i<=(int)end;i++)
#define RFOR(i,start,end) for(int i = start; i>end; i--)
#define RFORE(i,start,end) for(int i = start; i>=end; i--)
#define all(a) a.begin(), a.end()
#define mt make_tuple
#define mp make_pair
#define v vector
#define sf scanf
#define pf printf
#define dvar(x) cout << #x << " := " << x << "\n"
#define darr(x,n) FOR(i,0,n) cout << #x << "[" << i << "]" << " := " << x[i] << "\n"

typedef long long ll;
typedef long double ld;
typedef pair<int, int > pii;
typedef pair<ll, ll> pll;
//template <class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<class T> void minn(T &a, T b) { a = min(a, b); }
template<class T> void maxx(T &a, T b) { a = max(a, b); }

void io() {
#ifdef LOCAL_PROJECT 
	freopen("input.in", "r", stdin); freopen("output.out", "w", stdout);
#else 
	/* online submission */

#endif 
	ios_base::sync_with_stdio(false); cin.tie(NULL);
}

const ll MOD = 1000000007LL;
const ll PRIME = 105943LL;
const ll INF = 1e18;
/****************************************************************/

const int MAXN = 300099;
int N, A[MAXN];
set<int> adj[MAXN];
int subtreeSize[MAXN];
ll ans = 0;

int computeSSize(int cur, int par) {
	subtreeSize[cur] = 1;
	for (auto neigh : adj[cur]) if (neigh != par)
		subtreeSize[cur] += computeSSize(neigh, cur);
	return subtreeSize[cur];
}
int getCentroid(int cur, int par) {
	computeSSize(cur, par);
	int maxsize = subtreeSize[cur] / 2; // all subtrees must be <= maxsize
	while (true) {
		int next = -1; // is there a child of cur with size > maxsize?
		for (auto neigh : adj[cur]) { // check all childs of cur
			if (neigh != par && subtreeSize[neigh] > maxsize) {
				next = neigh;
				break;
			}
		}
		if (next == -1) { // cur is a centroid
			return cur;
		}
		par = cur;
		cur = next;
	}
	return -10000; // ERROR
}

struct dat {
	int x, u, d;
	dat(int a, int b, int c) : x(a), u(b), d(c) {}
};
void dfs(int i, int p, v<dat> &tab, int pidx) {
	if (pidx == -1) {
		tab.push_back(dat(A[i], A[i], A[i]));
	}
	else {
		dat cur(0, 0, 0);
		cur.x = A[i] + tab[pidx].x;
		cur.u = min(A[i], A[i] + tab[pidx].u);
		cur.d = min(tab[pidx].d, cur.x);
		tab.push_back(cur);
	}
	int iidx = tab.size() - 1;
	for (auto c : adj[i]) if (c != p) {
		dfs(c, i, tab, iidx);
	}
}

void dfsSolve(int root) {
	root = getCentroid(root, -1);
	int R = A[root];
//	cout << root << " root \n";
	v<v<dat>> table;
	map<int, int> cnt;
	for (auto c : adj[root]) {
		table.push_back(v<dat>());
		dfs(c, root, table.back(), -1);
		for (auto t : table.back()) {
			if (t.x + R == 0 && t.u >= 0)
				ans++;
			if (t.x + R == 0 && t.d + R >= 0 && R >= 0)
				ans++;
			if (t.d >= t.x)
				cnt[t.x]++;
		}
	//	cout << c << ":\n";
	//	for (auto t : table.back())
	//		cout << t.x << " x " << t.u << " u " << t.d << " d \n";
	}
	for (auto &sub : table) {
		for (auto t : sub) if (t.d >= t.x)	cnt[t.x]--;
		for (auto t : sub) {
			if (t.u >= 0 && t.x + R >= 0) {
				auto it = cnt.find(-(t.x + R));
				if (it != cnt.end())
					ans += it->second;
			}
		}
		for (auto t : sub) if (t.d >= t.x)	cnt[t.x]++;
	}
	for (int subt : adj[root]) {
		adj[subt].erase(root);
		dfsSolve(subt);
	}
}

int main() {
	io();
	cin >> N;
	string s;
	cin >> s;
	FOR(i, 0, N) A[i + 1] = s[i] == '(' ? 1 : -1;
	FOR(i, 0, N - 1) {
		int a, b;
		cin >> a >> b;
		adj[a].insert(b), adj[b].insert(a);
	}
	dfsSolve(1);
	cout << ans << "\n";
	return 0;
}

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