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https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
26 lines
472 B
C++
26 lines
472 B
C++
#include<iostream>
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#include<cstring>
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using namespace std;
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const int MAX=3000004;
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long long e[MAX];
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void euler()
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{
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e[1]=0;
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for(int i=2;i<MAX;++i)
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e[i]=i;
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for(int i=2;i<MAX;++i)
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if(e[i]==i)
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for(int j=i;j<MAX;j+=i)
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e[j]=e[j]/i*(i-1);
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for(int i=2;i<MAX;++i)
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e[i]+=e[i-1];
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}
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int main()
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{
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euler();
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int a,b;
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while(cin>>a>>b)
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cout<<e[b]-e[a-1]<<endl;
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return 0;
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}
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