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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3. #define int              long long int
  4. #define double           long double
  5. inline int power(int a, int b) {
  6.     int x = 1;
  7.     while (b) {
  8.         if (b & 1) x *= a;
  9.         a *= a;
  10.         b >>= 1;
  11.     }
  12.     return x;
  13. }
  14.  
  15.  
  16. const int M = 1000000007;
  17. const int N = 3e5+9;
  18. const int INF = 2e9+1;
  19. const int LINF = 2000000000000000001;
  20.  
  21. //_ ***************************** START Below *******************************
  22.  
  23. // 12
  24. // ab ab ba ba ee ee ee ff ff ff gg gg
  25.  
  26. vector<string> a;
  27. void consistency(int n) {
  28.  
  29. 	unordered_map<string, int> mp, aa;
  30. 	int ans = 0;
  31.  
  32. 	for(auto& w : a){
  33. 		string rev(w);
  34. 		swap(rev[0], rev[1]);
  35.  
  36. 		if(w[0] == w[1]){
  37. 			aa[w]++;
  38. 			continue;
  39. 		}
  40.  
  41. 		if(mp.count(rev)){
  42. 			mp[rev]--;
  43. 			if(mp[rev]==0) mp.erase(rev);
  44. 			ans += 2;
  45. 		}
  46. 		else{
  47. 			mp[w]++;
  48. 		}
  49. 	}
  50.  
  51. 	int odd = 0;
  52. 	for(auto& it : aa){
  53. 		int ct = it.second;
  54. 		if(ct & 1){
  55. 			odd++;
  56. 			ans += ct-1;
  57. 		}
  58. 		else ans += ct;
  59. 	}
  60.  
  61. 	if(odd) ans++;
  62.  
  63. 	cout << 2*ans << endl;
  64.  
  65.  
  66. }
  67.  
  68. void solve() {
  69.  
  70.     int n;
  71.     cin >> n;
  72.     a.resize(n);
  73.     for(int i=0; i<n; i++) cin >> a[i];
  74.  
  75.     consistency(n) ;
  76.  
  77. }
  78.  
  79.  
  80.  
  81.  
  82.  
  83. int32_t main() {
  84.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  85.  
  86.     int t = 1;
  87.     while (t--) {
  88.         solve();
  89.     }
  90.  
  91.     return 0;
  92. }
Success #stdin #stdout 0s 5328KB
comments (?)
stdin
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12
ab ab ba ba ee ee ee ff ff ff gg gg
stdout
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22
https://ideone.com/jSrLml
language:
C++14 (gcc 8.3)
created:
2 hours ago
visibility:
public

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