78 lines
1.4 KiB
C++
78 lines
1.4 KiB
C++
#include<stdio.h>
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#include<string.h>
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#define N 2010
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#define K 510
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char mol[K][N],den[K][N];
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char virt[N];
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int gcd(int a,int b)
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{
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return b?gcd(b,a%b):a;
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}
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int divide(char *str,int n,char *s)
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{
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int i,k,len;
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len=strlen(str);
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s[len]=0;
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for(k=0,i=len-1;i>=0;i--)
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{
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k=k*10+str[i]-'0';
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s[i]=k/n+'0';
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k%=n;
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}
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for(i=len-1;i>0;i--)
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{
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if(s[i]!='0')
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break;
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s[i]=0;
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}
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return k;
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}
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void mult(char *str,int n,char *x)
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{
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int i,s[N];
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for(i=0;i<N;i++)
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s[i]=0;
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for(i=0;str[i];i++)
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s[i]=(str[i]-'0')*n;
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for(i=0;i<N-1;i++)
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{
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s[i+1]+=s[i]/10;
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s[i]%=10;
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}
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for(i=N-1;i>0 && s[i]==0;i--);
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x[i+1]=0;
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for(;i>=0;i--)x[i]=s[i]+'0';
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}
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void init()
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{
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int i,j,k;
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strcpy(mol[1],"1");
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strcpy(den[1],"2");
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for(i=2;i<K;i++)
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{
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j=2*i;
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k=gcd(j,divide(mol[i-1],j,virt));
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divide(mol[i-1],k,mol[i]);
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mult(den[i-1],j/k,den[i]);
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j--;
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k=gcd(j,divide(den[i],j,virt));
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if(k>1)
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divide(den[i],k,den[i]);
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mult(mol[i],j/k,mol[i]);
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strrev(mol[i-1]);
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strrev(den[i-1]);
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}
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}
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int main()
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{
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int n,T;
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init();
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scanf("%d",&T);
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while(T--)
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{
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scanf("%d",&n);
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printf("%s/%s\n",mol[n],den[n]);
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}
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return 0;
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}
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