UVa202Repeating Decimals (循環小數)

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解答：

因為除數是固定的，所以只要判斷被除數是否出現過即可。

#include<iostream>
#include <cstdio>
#include <cstring>
using namespace std;
int m,n,vis[5000],res[5000],temp[5000],num,t,x;
int main()
{while(scanf("%d%d",&m,&n)==2) {memset(vis,0,sizeof(vis));memset(res,0,sizeof(res));memset(temp,0,sizeof(temp));x = m/n;num=0;t=m;m=m%n;   while(vis[m]==0&&m!=0){vis[m]=1;temp[m]=num;res[num]=m*10/n;num++;m=m*10%n;   }if (m==0){printf("%d/%d = %d.",t,n,x);for (int i=0;i<num;++i)cout<<res[i];printf("(0)\n   1 = number of digits in repeating cycle\n");}else{printf("%d/%d = %d.",t,n,x);for(int i=0;i<temp[m];++i) printf("%d",res[i]);printf("(");if(num-temp[m]>50){for (int i=temp[m];i<50+temp[m];++i) printf("%d",res[i]);printf("...");}elsefor (int i=temp[m];i<num;++i) printf("%d",res[i]);printf(")\n   %d = number of digits in repeating cycle\n",num-temp[m]);}printf("\n");}return 0;
}

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