The left rotation string of the sword (42)

Title Description

In assembly language, there is a shift instruction called the cyclic left shift (ROL), now there is a simple task, is to use a string to simulate the operation of the command results. For a given character sequence s, you turn the output of the sequence to the left of the K-bit after it is moved. For example, the character sequence s= "Abcxyzdef", which requires the output loop to move left 3 bits after the result, i.e. "XYZDEFABC". Isn't it simple? OK, Fix it!

<span style= "color: #33cc00;" >public class Solution {public    string leftrotatestring (String str,int N) {        if (Str.trim (). Length () ==0) {            return str;        }        StringBuilder rol=new StringBuilder ();        Rol.append (str.substring (n));        Rol.append (str.substring (0,n));        return rol.tostring ();    }} </span>

The left rotation string of the sword (42)