23 lines
457 B
C++
23 lines
457 B
C++
#include <iostream>
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#include <algorithm>
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using namespace std;
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bool pan[1000001]={0};
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int main()
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{
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int begn, ends;
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cin >> begn >> ends;
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for (int i = 2; i * i <= ends; i++) {
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for(int j=ends/i;i*j>=begn&&j!=1;j--){
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pan[i*j-begn]=1;
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}
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}
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int ans=0;
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for(int i=0;i<=ends-begn;i++){
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if(pan[i]==0){
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ans++;
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//cout<<begn+i<<" ";
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}
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}
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cout<<ans;
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}
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