16 lines
215 B
C++
16 lines
215 B
C++
//½×¼Ó£¨³¬Ð¡£©
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#include <iostream>
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using namespace std;
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long long dg(long long n){
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if(n==1){
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return 1;
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}
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return n+dg(n-1);
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}
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int main()
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{
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int n;
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cin>>n;
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cout<<dg(n);
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}
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