LintCode-Rotate String

Given a string and an offset, rotate string by offset. (rotate from left to right)

Example

Given "abcdefg"

for offset=0, return "abcdefg"

for offset=1, return "gabcdef"

for offset=2, return "fgabcde"

for offset=3, return "efgabcd"

Solution:

public class Solution {
    /*
     * param A: A string
     * param offset: Rotate string with offset.
     * return: Rotated string.
     */
    public char[] rotateString(char[] A, int offset) {
        if (A.length==0) return A;
        offset = offset % A.length;
        if (offset == 0) return A;
        int len = A.length;
        //Store the rotated char in buffer.
        char[] buff = new char[offset];
        for (int i=len-offset;i<len;i++)
            buff[i-len+offset] = A[i];

        //Move the left chars to right.
        for (int i=len-offset-1;i>=0;i--)
            A[i+offset] = A[i];

        //Put the chars in buff into array.
        for (int i=0;i<offset;i++)
            A[i] = buff[i];

        return A;
    }
};