8. 旋轉字符串

思路

給定一個字符串和一個偏移量，根據偏移量旋轉字符串(從左向右旋轉)
樣例
    對於字符串 "abcdefg".
    offset=0 => "abcdefg"
    offset=1 => "gabcdef"
    offset=2 => "fgabcde"
    offset=3 => "efgabcd"

Python

class Solution:
    """
    @param str: An array of char
    @param offset: An integer
    @return: nothing
    """

    def rotateString(self, str, offset):
        # write your code here
        if not offset:
            return
        if not str:
            return
        str_length = len(str)
        offset %= str_length
        for i in range(offset):
            ch = str.pop()
            str.insert(0, ch)


if __name__ == "__main__":
    s = Solution()
    ss = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
    s.rotateString(ss, 0)
    s.rotateString(ss, 1)
    s.rotateString(ss, 2)
    s.rotateString(ss, 3)

Go

package main

/**
 * @param str: An array of char
 * @param offset: An integer
 * @return: nothing
 */
func rotateString(str *string, offset int) {
    // write your code here
    strLength := len(*str)
    if strLength == 0 {
        return
    }
    offset %= strLength
    rotateStr := (*str)[strLength-offset:] + (*str)[:strLength-offset]
    *str = rotateStr
}

func main() {
    str, offset := "abcdefg", 1
    rotateString(&str, offset)
    str, offset = "", 10
    rotateString(&str, offset)

}