元素翻转

读编程珠玑，得知的两种元素串翻转方法，我简单实现了下

第一种是杂技翻转取模替换

 1 int gcd(int i, int j)
 2 {
 3     while (i != j)
 4         if (i > j)
 5             i -= j;
 6         else
 7             j -= i;
 8     return i;        
 9 }
10 
11 int main()
12 {
13     freopen("datain.txt", "r", stdin);
14     int i, rotdist, n;
15     char x[] = {"12345678"};
16     scanf("%d %d", &rotdist, &n);
17     for (i = 0; i < gcd(rotdist, n); i++)
18     {
19         int k, t = x[i], j = i;
20         while(1)
21         {
22             k = j + rotdist; 
23             if (k >= n)
24                 k -= n;
25             if (k == i)
26                 break;
27             x[j] = x[k];
28             j = k;
29         }
30         x[j] = t;
31     }
32     printf("%s", x);
33     getch();
34     return 0;
35 }

第二种是求逆翻转相比之前方法要好

#include <stdio.h>

char a[] = {"123456789"};
void reverse(int pos, int n)
{
    int i;
    for (i = pos; i < (n+pos+1)/2; i++)
    {
        char t = a[i];
        a[i] = a[n+pos+1 - i - 1];
        a[n+pos+1 - i - 1] = t;
    }
    return ; 
}

int main()
{
    int rotdist =3, n = 9;
    reverse(0, 2);
    reverse(3, 8);
    reverse(0, 8);
    printf("%s", a);
    getch();
    return 0;
}