UVA - 202 Repeating Decimals

Repeating Decimals

 UVA - 202 

题目传送门

解决方法：模拟一下除法，及时记录余数，当一个余数第二次出现时证明开始循环

AC代码

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <map>
#include <stack>
#include <queue>
#include <vector>
#include <bitset>
#include <set>
#include <utility>
#include <sstream>
#include <iomanip>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define inf 0x3f3f3f3f
#define rep(i,l,r) for(int i=l;i<=r;i++)
#define lep(i,l,r) for(int i=l;i>=r;i--)
#define ms(arr) memset(arr,0,sizeof(arr))
//priority_queue<int,vector<int> ,greater<int> >q;
const int maxn = (int)1e5 + 5;
const ll mod = 1e9+7;
int yushu[maxn];
int shang[maxn];
int wei[maxn];
int main() 
{
    #ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    #endif
    //freopen("out.txt", "w", stdout);
    ios::sync_with_stdio(0),cin.tie(0);
    int n,m;
    int cnt=0;
    while(scanf("%d %d",&n,&m)!=EOF)
    {
    	int k=n;
    	ms(yushu);ms(shang);ms(wei);
    	int count=0;
    	shang[count++]=n/m;
    	n=n%m;
    	while(!wei[n]&&n)
    	{
    		wei[n]=count;
    		yushu[count]=n;
    		shang[count++]=n*10/m;
    		n=n*10%m;
    	}
    	printf("%d/%d = %d.",k,m,shang[0]);
    	int i;
    	for(i=1;i<count&&i<=50;i++)
    	{
    		if(yushu[i]==n&&n)
    			printf("(");
    		printf("%d",shang[i]);
    	}
    	if(n==0)
    		printf("(0");
    	if(count>50)
    		printf("...");
    	printf(")\n");
    	printf("   %d = number of digits in repeating cycle\n\n",!n?1:count-wei[n]);
    }
    return 0;
}