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  1. /*
  2.     Cred : SunnyYeahBoi
  3.     It's my last chance (⌐■_■)
  4.     Problem :
  5. */
  6.  
  7. #include<bits/stdc++.h>
  8.  
  9. using namespace std;
  10.  
  11. #define int long long
  12. #define double long double
  13. #define endl "\n"
  14. #define NAME "a"
  15.  
  16. const int MAXN = 1e6 + 5;
  17. const int inf = 1e18;
  18. const int MOD = 1e9 + 7;
  19.  
  20. void FileInput(){
  21.     if(fopen(NAME".inp" , "r") == NULL)
  22.         freopen(NAME".inp" , "w" , stdout);
  23.     freopen(NAME".inp" , "r" , stdin);
  24.     freopen(NAME".out" , "w" , stdout);
  25. }
  26.  
  27. int n;
  28. string s;
  29. int pref[MAXN];
  30.  
  31. void solve(){
  32.     cin >> n;
  33.     cin >> s;
  34.     s = "*" + s;
  35.  
  36.     for(int i = 1 ; i <= n ; i++){
  37.         pref[i] = pref[i - 1] + (s[i] == '(' ? 1 : -1);
  38.     }
  39.  
  40.     for(int i = n + 1 ; i <= 2 * n ; i++)
  41.         pref[i] = pref[i - 1] + (s[i - n] == '(' ? 1 : -1);
  42.  
  43.  
  44.     int res = 0;
  45.     deque<int> q; // queue tìm min 
  46.     for(int i = 1 ; i <= 2 * n ; i++){
  47.         while(!q.empty() && pref[q.back()] >= pref[i])
  48.             q.pop_back();
  49.         q.push_back(i);
  50.         if(q.front() < i - n + 1) q.pop_front();
  51.  
  52.         // i - n + 1 ; i
  53.         if(i >= n){
  54.             bool ok1 = (pref[i] - pref[i - n] == 0);
  55.             bool ok2 = (pref[q.front()] - pref[i - n] >= 0);
  56.             res += (ok1 && ok2);
  57.         }
  58.     }
  59.  
  60.     cout << res << endl;
  61. }
  62.  
  63. int32_t main(){
  64.     FileInput();
  65.     ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
  66.     int t = 1;
  67.     // cin >> t;
  68.     while(t--)
  69.         solve();
  70.     return 0;
  71. }
  72.  
Success #stdin #stdout 0.01s 5236KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/ht0Pn5
language:
C++14 (gcc 8.3)
created:
6 days ago
visibility:
public

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