Smallest Cyclic Shift

/*
 * Findin lex smallest cyclic shift of a string
 * Algorithm :
 * Order : Linear O( n )
 */
#include<string>
using namespace std;
/* min_ind contains the lowest index of s( 0 based ) which is the cyclic lex smallest */
long MinCyclicShift( string s ){
    s += s;
    long n = s.length();
    long i = 0,min_ind = 0;
    while( i < n/2 ){
        min_ind = i;
        long j = i+1, k = i;
        while( j<n && s[k] <= s[j] ){
            if( s[k] < s[j] ) k = i;
            else k++;
            ++j;
        }
        while( i<=k )  i += j-k;
    }
    return min_ind;
}