Uniform Generator

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 21219    Accepted Submission(s):
8308

Problem Description

Computer simulations often require random numbers. One
way to generate pseudo-random numbers is via a function of the
form

seed(x+1) = [seed(x) + STEP] % MOD

where ‘%‘ is the modulus
operator.

Such a function will generate pseudo-random numbers (seed)
between 0 and MOD-1. One problem with functions of this form is that they will
always generate the same pattern over and over. In order to minimize this
effect, selecting the STEP and MOD values carefully can result in a uniform
distribution of all values between (and including) 0 and MOD-1.

For
example, if STEP = 3 and MOD = 5, the function will generate the series of
pseudo-random numbers 0, 3, 1, 4, 2 in a repeating cycle. In this example, all
of the numbers between and including 0 and MOD-1 will be generated every MOD
iterations of the function. Note that by the nature of the function to generate
the same seed(x+1) every time seed(x) occurs means that if a function will
generate all the numbers between 0 and MOD-1, it will generate pseudo-random
numbers uniformly with every MOD iterations.

If STEP = 15 and MOD = 20,
the function generates the series 0, 15, 10, 5 (or any other repeating series if
the initial seed is other than 0). This is a poor selection of STEP and MOD
because no initial seed will generate all of the numbers from 0 and MOD-1.

Your program will determine if choices of STEP and MOD will generate a
uniform distribution of pseudo-random numbers.

Input

Each line of input will contain a pair of integers for
STEP and MOD in that order (1 <= STEP, MOD <= 100000).

Output

For each line of input, your program should print the
STEP value right- justified in columns 1 through 10, the MOD value
right-justified in columns 11 through 20 and either "Good Choice" or "Bad
Choice" left-justified starting in column 25. The "Good Choice" message should
be printed when the selection of STEP and MOD will generate all the numbers
between and including 0 and MOD-1 when MOD numbers are generated. Otherwise,
your program should print the message "Bad Choice". After each output test set,
your program should print exactly one blank line.

Sample Input

3 5
15 20
63923 99999

Sample Output

    3       5     Good Choice
   15      20     Bad Choice 63923   99999     Good Choice

//考虑大数；注意格式；

 1 #include<stdio.h>
 2 #define MAX 100010;
 3
 4 int gcd(int a, int b)    //最大公约数；
 5 {
 6     if(!b) return a;
 7     else
 8     return gcd(b,a%b);
 9 }
10
11 int main()
12 {
13     int m,n;
14     while(~scanf("%d %d",&m,&n))
15     {
16         int len=gcd(m,n);
17         if(len==1)
18         printf("%10d%10d    Good Choice\n\n");
19         else
20         printf("%10d%10d    Bad Chioce\n\n");
21
22     }
23 } 

 1 #include<stdio.h>
 2 int main()
 3 {
 4     int m,n;
 5     while(~scanf("%d %d",&m,&n))
 6     {
 7         printf("%10d%10d",m,n);
 8         int total=0,i;
 9         for(i=0;;i++)
10         {
11             total=(total+m)%n;
12             if(total==0)
13             break;
14         }
15         if(i==n-1)
16         printf("    Good Choice\n");
17         else
18         printf("    Bad Choice\n");
19         printf("\n");
20
21     }
22     return 0;
23 }