void ShellSort ( vector
     
       &v ) {    int P = 4;    int m[] = {
   5,3,2,1};    for ( int idx = 0; idx < P; idx++ ) {        int len = m[idx];        for ( int sec = 1; sec < ( v.size()/len + ( v.size()%len != 0 ) ); sec++ ) {            int end = ( sec*len + len ) < v.size() ? ( sec*len + len ) : v.size();            for ( int i = sec*len; i < end; i++ ) {                for ( int j = ( sec - 1 ) * len; j < ( sec - 1 ) * len + len; j++ ) {                    if ( v[i] < v[j] ) {                        int t = v[i];                        v[i] = v[j];                        v[j] = t;                    }                }            }        }    }}