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https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
24 lines
369 B
C++
24 lines
369 B
C++
#include<iostream>
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using namespace std;
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#include<cstring>
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#include<stdio.h>
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double a[100005];
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int main()
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{
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int i,j,k;
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int N;
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a[0]=0;
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a[1]=1;
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a[2]=3.0;
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for(i=3;i<100001;i++)
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{
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k=(1+i)/2;
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a[i]=a[k-1]+k-1+a[i-k]+i-k+1;
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}
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while(cin>>N)
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{
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printf("%.2lf\n",a[N]/N);
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}
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return 0;
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}
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