int vec_rotate(char *vec,int rotdist, int length) {    int i,j,k,times;    char t;    times = gcd(rotdist,length);    printf("%d\n",times);    for(i=0;i<times;i++) {        t = vec[i];        j = i;        while(1) {            k = j+ rotdist;            if(k>=length)                k-=length;            if(k==i)                break;            vec[j] = vec[k];            j = k;        }        vec[j]=t;    }    return 0;}向量左旋算法1:"杂技"代码