57 lines
916 B
C++
57 lines
916 B
C++
#include<iostream>
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#include<cstring>
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using namespace std;
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int a[100000],n,i,y,xy[100000],s[100000];
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void add()
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{
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int i;
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memset(xy,0,sizeof(xy));
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xy[0]=max(s[0],a[0]);
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for (i=1;i<=xy[0];i++)
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{
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xy[i]+=s[i]+a[i];
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xy[i+1]=xy[i]/10;
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xy[i]%=10;
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}
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while (xy[xy[0]+1]>0)
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{
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xy[xy[0]+2]=xy[xy[0]+1]/10;
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xy[xy[0]+1]%=10;
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xy[0]++;
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}
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s[0]=xy[0];
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for (i=1;i<=xy[0];i++) s[i]=xy[i];
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}
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int main()
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{
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cin>>n;
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a[0]=1;
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a[1]=1;
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s[0]=1;
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s[1]=0;
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for (y=1;y<=n;y++)
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{
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memset(xy,0,sizeof(xy));
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xy[0]=a[0];
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for (i=1;i<=a[0];i++)
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{
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xy[i]+=a[i]*y;
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xy[i+1]=xy[i]/10;
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xy[i]%=10;
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}
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while (xy[xy[0]+1]>0)
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{
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xy[xy[0]+2]=xy[xy[0]+1]/10;
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xy[xy[0]+1]%=10;
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xy[0]++;
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}
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for (i=1;i<=xy[0];i++) a[i]=xy[i];
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a[0]=xy[0];
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add();
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}
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for (i=s[0];i>=1;i--) cout<<s[i];
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cout<<endl;
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return 0;
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}
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