제출 #586772

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
586772		MilosMilutinovic	Zagrade (COI17_zagrade)	C++14	100 / 100	1052 ms	57668 KiB

zagrade

/**
 *    author:  wxhtzdy
 *    created: 30.06.2022 10:05:38
**/
#include <bits/stdc++.h>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);  
  int n;
  cin >> n;
  string s;
  cin >> s;
  vector<vector<int>> g(n);
  for (int i = 0; i < n - 1; i++) {
    int u, v;
    cin >> u >> v;
    --u; --v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  vector<bool> was(n);
  vector<int> sz(n);
  function<void(int, int)> Dfs = [&](int v, int pr) {
    sz[v] = 1;
    for (int u : g[v]) {
      if (u == pr || was[u]) {
        continue;
      }
      Dfs(u, v);
      sz[v] += sz[u];
    }
  };
  function<int(int, int, int)> Find = [&](int v, int pr, int n) {
    for (int u : g[v]) {
      if (u == pr || was[u] || sz[u] * 2 < n) {
        continue;
      }
      return Find(u, v, n);
    }
    return v;
  };
  map<int, int> cnt;
  long long ans = 0;
  function<void(int, int, int, int, int)> Go = [&](int v, int pr, int bal, int mn, int f) {
    int me = (s[v] == '(' ? 1 : -1);
    bal += me;
    mn = min(me, me + mn);
    if (mn >= 0) {
      cnt[bal] += f;
    }
    for (int u : g[v]) {
      if (u == pr || was[u]) {
        continue;
      }
      Go(u, v, bal, mn, f);
    }
  };
  function<void(int, int, int, int)> Run = [&](int v, int pr, int bal, int mn) {
    bal += (s[v] == '(' ? +1 : -1);
    mn = min(mn, bal);
    if (mn == 0 && bal == 0) {
      ans += 1;
    }
    if (-bal + mn >= 0) {
      ans += cnt[-bal];      
    }
    for (int u : g[v]) {
      if (u == pr || was[u]) {
        continue;
      }
      Run(u, v, bal, mn);
    }
  };          
  function<void(int)> Solve = [&](int v) {
    Dfs(v, v);
    v = Find(v, v, sz[v]);
    was[v] = true;
    cnt.clear();
    for (int u : g[v]) { 
      if (was[u]) {
        continue;
      }
      Go(u, v, 0, 1, +1);     
    }       
    if (s[v] == ')') {
      ans += cnt[1];
    }     
    for (int u : g[v]) {
      if (was[u]) {
        continue;
      }
      int me = (s[v] == '(' ? +1 : -1);
      Go(u, v, 0, 1, -1);
      Run(u, v, me, me);
      Go(u, v, 0, 1, +1);     
    }
    for (int u : g[v]) {
      if (!was[u]) {
        Solve(u);
      }
    }
  };
  Solve(0);
  cout << ans << '\n';                    
  return 0;
}

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