UVa202 ACM/ICPC 1990 循环小数

The decimal expansion of the fraction 1/33 is 0.03, where the 03 is used to indicate that the cycle 03repeats indefinitely with no intervening digits. In fact, the decimal expansion of every rational number(fraction) has a repeating cycle as opposed to decimal expansions of irrational numbers, which have nosuch repeating cycles.

Examples of decimal expansions of rational numbers and their repeating cycles are shown below.Here, we use parentheses to enclose the repeating cycle rather than place a bar over the cycle.

           fraction                   decimal expansion                    repeating cycle                                   cycle length

             1/6                                0.1(6)                                            6                                                     1 

              5/7                            0.(714285)                                   714285                                               6

            1/250                           0.004(0)                                           0                                                    1

           300/31                    9.(677419354838709)             677419354838709                                      15

          655/990                            0.6(61)                                          61                                                  2

Write a program that reads numerators and denominators of fractions and determines their repeatingcycles.For the purposes of this problem, define a repeating cycle of a fraction to be the first minimal lengthstring of digits to the right of the decimal that repeats indefinitely with no intervening digits. Thusfor example, the repeating cycle of the fraction 1/250 is 0, which begins at position 4 (as opposed to 0which begins at positions 1 or 2 and as opposed to 00 which begins at positions 1 or 4).InputEach line of the input file consists of an integer numerator, which is nonnegative, followed by an integerdenominator, which is positive. None of the input integers exceeds 3000. End-of-file indicates the endof input.

#include
#include
int a[5000],b[5000],c[5000];  
int main(void)  
{  
    int n,m,t;  
    while (~scanf("%d%d",&n,&m)) 
{  
        t=n;  
        memset(a,0,sizeof(a));  
        memset(b,0,sizeof(b));  
        int count=0;  
        a[count++]=n/m;//将整数部分储存起来  
        n=n%m;  //取余数 
        while(b[n]==0&&n!=0){  
            b[n]=count; //将余数在数组中的位置都标记出来，使循环次数t能在0<=t 50) printf("...");  
        printf(")\n");
if(n!=0)
        printf("   %d = number of digits in repeating cycle\n\n",count-b[n]);
        else
        printf("   %d = number of digits in repeating cycle\n\n",1);//一位循环数  
    }  
    return 0;  
} //本题主要关键点有两点，其它要注意的是解题的规范性和细心
//1余数最多的数量顶多为m
//2将余数记录下来是找到循环开始是关键