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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.  
  24.  
  25. vector<string> a;
  26. void consistency(int n) {
  27.  
  28. 	unordered_map<string, int> mp, aa;
  29. 	int ans = 0;
  30.  
  31. 	for(auto& w : a){
  32. 		string rev(w);
  33. 		swap(rev[0], rev[1]);
  34.  
  35. 		if(w[0] == w[1]){
  36. 			aa[w]++;
  37. 			continue;
  38. 		}
  39.  
  40. 		if(mp.count(rev)){
  41. 			mp[rev]--;
  42. 			if(mp[rev]==0) mp.erase(rev);
  43. 			ans += 2;
  44. 		}
  45. 		else{
  46. 			mp[w]++;
  47. 		}
  48. 	}
  49.  
  50. 	int odd = 0;
  51. 	for(auto& it : aa){
  52. 		int ct = it.second;
  53. 		if(ct & 1){
  54. 			odd++;
  55. 			ans += ct-1;
  56. 		}
  57. 		else ans += ct;
  58. 	}
  59.  
  60. 	if(odd) ans++;
  61.  
  62. 	cout << 2*ans << endl;
  63.  
  64.  
  65. }
  66.  
  67. void solve() {
  68.  
  69.     int n;
  70.     cin >> n;
  71.     a.resize(n);
  72.     for(int i=0; i<n; i++) cin >> a[i];
  73.  
  74.     consistency(n) ;
  75.  
  76. }
  77.  
  78.  
  79.  
  80.  
  81.  
  82. int32_t main() {
  83.     ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  84.  
  85.     int t = 1;
  86.     while (t--) {
  87.         solve();
  88.     }
  89.  
  90.     return 0;
  91. }
Success #stdin #stdout 0.01s 5320KB
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stdout
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https://ideone.com/LGv0A7
language:
C++14 (gcc 8.3)
created:
1 day ago
visibility:
public

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