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  1. #include <bits/stdc++.h>
  2.  
  3. using namespace std;
  4.  
  5. #define ll long long
  6. #define initial first
  7. #define added second
  8.  
  9. #define EGRY                          \
  10.     ios_base::sync_with_stdio(false); \
  11.     cin.tie(NULL);
  12.  
  13. const int MAX = 100 + 50;
  14. const int MOD = 998244353;
  15. const int OO = INT_MAX;
  16.  
  17. const double EPS = (double)1e-9;
  18.  
  19. void solve()
  20. {
  21.     string n, org;
  22.     cin >> n;
  23.     vector<string> p;
  24.  
  25.     org = n;
  26.     sort(n.begin(), n.end());
  27.  
  28.     do
  29.     {
  30.         p.push_back(n);
  31.     } while (next_permutation(n.begin(), n.end()));
  32.  
  33.     double fact = (int)p.size();
  34.  
  35.     if (org == p[fact - 1])
  36.     {
  37.         cout << fixed << setprecision(9) << 0.0 << endl;
  38.         return;
  39.     }
  40.  
  41.     double res = 1.0 / fact;
  42.  
  43.     if (org == p[fact - 2])
  44.     {
  45.         cout << fixed << setprecision(9) << res << endl;
  46.         return;
  47.     }
  48.  
  49.     for (int i = fact - 3; i >= 0; i--)
  50.     {
  51.         res = res + (1.0 / fact) * res;
  52.         if (p[i] == org)
  53.         {
  54.             cout << fixed << setprecision(9) << res << endl;
  55.         }
  56.     }
  57. }
  58.  
  59. int main()
  60. {
  61.     EGRY int t = 1;
  62.     cin >> t;
  63.  
  64.     while (t--)
  65.     {
  66.         solve();
  67.     }
  68.     return 0;
  69. }
  70.  
Success #stdin #stdout 0s 5288KB
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Standard input is empty
stdout
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0.000000000
https://ideone.com/vWjPd2
language:
C++14 (gcc 8.3)
created:
17 hours ago
visibility:
public

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