23 lines
288 B
C++
23 lines
288 B
C++
#include <stdio.h>
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#include <string.h>
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const int N = 50005;
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double p[N];
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void init()
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{
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p[1]=1;
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for(int i=1;i<50000;i++)
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p[i+1]=p[i]*(2*i-1)/(2*i);
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}
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int main()
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{
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init();
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int cas,n;
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scanf("%d", &cas);
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while(cas--)
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{
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scanf("%d",&n);
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printf("%.4lf\n",1-p[n/2]);
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}
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return 0;
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}
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