34 lines
838 B
C++
34 lines
838 B
C++
#include<cstdio>
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#include<cstring>
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using namespace std;
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int num[2][100000];
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int main()
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{
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int n,m,k;
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while(scanf("%d%d%d",&n,&m,&k)!=EOF&&(n||m||k))
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{
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memset(num,0,sizeof(num));
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for(int i=1; i<=m; i++)
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num[1][i]=1;
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for(int i=2; i<=n; i++)
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{
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for(int j=1; j<=i*m; j++)
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for(int l=1; l<=m; l++)
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num[i%2][j+l]+=num[(i-1)%2][j];
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memset(num[(i-1)%2],0,sizeof(num[(i-1)%2]));
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}
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double res=0.0;
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int i,j;
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for(i=1; i<=k+1; i++)
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res+=num[n%2][i];
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for(j=2;i<=n*m; i++,j++)
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res+=num[n%2][i]*j;
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int count=1;
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for(int i=1;i<=n;i++)
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count*=m;
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res/=count;
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printf("%.8lf\n",res);
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}
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return 0;
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}
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