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  1. #include <bits/stdc++.h>
  2. using namespace std;
  3.  
  4. #define ll long long
  5. #define mset(arr,x) memset(arr,x,sizeof(arr))
  6. #define rep(i,s,e) for(i=s;i<=e;i++)
  7. #define rrep(i,s,e) for(i=s;i>=e;i--)
  8.  
  9. ll dp[4010][4010];
  10. int main()
  11. {
  12.     ios_base::sync_with_stdio(false);
  13.     cin.tie(0);
  14.  
  15.     ll N, i, j, T, M, ppll;
  16.     string st;
  17.  
  18.     cin >> T;
  19.     rep(ppll, 1, T)
  20.     {
  21.        mset(dp, 0);
  22.  
  23.        cin >> N >> M;
  24.        rep(i, 1, N)
  25.        {
  26.            dp[i][0] = 1;
  27.        }
  28.  
  29.        rep(i, 1, N)
  30.        {
  31.            rep(j, 1, i-1)
  32.            {
  33.                if( i!=j )
  34.                {
  35.                    dp[i][j] = dp[i-1][j] + dp[i][j-1];
  36.                }
  37.            }
  38.        }
  39.  
  40.        double anss = (double)dp[N][M];
  41.        ll val = N+M;
  42.  
  43.        rrep(i, M, 1)
  44.        {
  45.            double opop = (double)( ((double)i)/val );
  46.            anss = ( anss * opop );
  47.            val--;
  48.        }
  49.  
  50.        cout << "Case #" << ppll << ": " << setprecision(12) << anss << endl;
  51.     }
  52.  
  53.     return 0;
  54. }
  55.  
Success #stdin #stdout 0.03s 140864KB
comments (?)
stdin 
2
2 1
1 0
stdout 
Case #1: 0.333333333333
Case #2: 1
https://ideone.com/7Ffer4
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
secret

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