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  1. #include <bits/stdc++.h>
  2.  
  3.  
  4. //_ ************************** Advanced PBDS ***********************************
  5.  
  6. #include <ext/pb_ds/assoc_container.hpp>
  7. #include <ext/pb_ds/tree_policy.hpp>
  8.  
  9. using namespace std;
  10. using namespace __gnu_pbds;
  11.  
  12. template<class T>
  13. using ordered_set = tree<
  14.     T,
  15.     null_type,
  16.     less<T>,
  17.     rb_tree_tag,
  18.     tree_order_statistics_node_update
  19. >;
  20.  
  21.  
  22. //_ ****************************************************************************
  23.  
  24.  
  25. #define int              long long int
  26. #define double           long double
  27. #define print(a)         for(auto x : a) cout << x << " "; cout << endl
  28.  
  29.  
  30. const int M = 1000000007;
  31. const int N = 3e5+9;
  32. const int INF = 2e9+1;
  33. const int LINF = 2000000000000000001;
  34.  
  35. inline int power(int a, int b, int mod=M) {
  36.     int x = 1;
  37.     a %= mod;
  38.     while (b) {
  39.         if (b & 1) x = (x * a) % mod; 
  40.         a = (a * a) % mod;
  41.         b >>= 1;
  42.     }
  43.     return x;
  44. }
  45.  
  46.  
  47. //_ ***************************** START Below *******************************
  48.  
  49. // 6
  50. // 0 1 1 0 1 1
  51.  
  52.  
  53. vector<int> a;
  54.  
  55. int consistency(int n){
  56.  
  57. 	ordered_set<pair<int,int>> st;
  58. 	st.insert({0,-1}); //* insert index for uniqueness 
  59.  
  60. 	int ans = 0;
  61. 	int sum = 0;
  62.  
  63. 	for(int i=0; i<n; i++){
  64. 		if(a[i] == 0) sum--;
  65. 		else sum++;
  66.  
  67. 		int ct = st.order_of_key({sum, -INF});
  68.  
  69. 		st.insert({sum,i});
  70. 		ans += ct;
  71.  
  72. 	}
  73.  
  74. 	return ans;
  75.  
  76. }
  77.  
  78.  
  79.  
  80.  
  81.  
  82.  
  83.  
  84.  
  85.  
  86.  
  87.  
  88.  
  89.  
  90.  
  91.  
  92. int practice(int n){
  93.  
  94.  
  95.     return 0;
  96. }
  97.  
  98.  
  99.  
  100.  
  101.  
  102. void solve() {
  103.  
  104.     int n;
  105.     cin>> n;
  106.  
  107.     a.resize(n);
  108.     for(int i=0; i<n; i++) cin >> a[i];
  109.  
  110.     cout << consistency(n) << endl;
  111.  
  112.  
  113. }
  114.  
  115.  
  116.  
  117.  
  118.  
  119. int32_t main() {
  120.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  121.  
  122.     int t = 1;
  123.     // cin >> t;
  124.     while (t--) {
  125.         solve();
  126.     }
  127.  
  128.     return 0;
  129. }
Success #stdin #stdout 0s 5288KB
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0 1 1 0 1 1
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https://ideone.com/VHUMdu
language:
C++14 (gcc 8.3)
created:
2 days ago
visibility:
public

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