23 lines
343 B
C++
23 lines
343 B
C++
#include <iostream>
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using namespace std;
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double ans[50];
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int vis[50];
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double dfunc(int n,int x)
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{
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if(n==0) return 1;
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if(n==1) return x;
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if(vis[n]) return ans[n];
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vis[n]=1;
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return ans[n]=double((2*n-1)*x*dfunc(n-1,x)-(n-1)*dfunc(n-2,x))/n;
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}
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int main()
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{
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int a,b;
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cin>>a>>b;
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cout<<dfunc(a,b);
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return 0;
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}
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