技術標籤：Java連結串列字串演算法資料結構leetcode

劍指 Offer 58 - II. 左旋轉字串

• • 題目網址
  • 題目描述
  • 樣例
  • code
  • 執行結果

題目網址

劍指 Offer 58 - II. 左旋轉字串

題目描述

字串的左旋轉操作是把字串前面的若干個字元轉移到字串的尾部。請定義一個函式實現字串左旋轉操作的功能。比如，輸入字串"abcdefg"和數字2，該函式將返回左旋轉兩位得到的結果"cdefgab"。

樣例

樣例1
輸入: s = “abcdefg”, k = 2
輸出: “cdefgab”
樣例2
輸入: s = “lrloseumgh”, k = 6

輸出: “umghlrlose”
限制：1 <= k < s.length <= 10000

code

class Solution {

    public String reverseLeftWords(String s, int n) {
        DoubleSignalLink link= initLink(s,new DoubleSignalLink(),n);
        return reverseLink(link,s);
    }

     //定義連結串列
    private static class DoubleSignalLink{
        char
 
 chr;
        DoubleSignalLink next;
        DoubleSignalLink pre;
        DoubleSignalLink(){
        }
        DoubleSignalLink(char data){
            this.chr=data;
        }
    }
    //初始化連結串列,通過連結串列進行左右的拆分
    private static DoubleSignalLink initLink(String str,DoubleSignalLink link,int target)
 
{
        char [] arr =str.toCharArray();
        DoubleSignalLink root =new DoubleSignalLink();
        DoubleSignalLink head=link;
        DoubleSignalLink tmp =root;
        int i=0,j=1;
        while (i<arr.length){
            DoubleSignalLink t =new DoubleSignalLink(arr[i]);
            if (j<=target){
                tmp.next=t;
                t.pre=tmp.next;
                tmp=tmp.next;
                j++;
            }
            else{
                head.next=t;
                t.pre=head.next;
                head=head.next;
            }
            i++;
        }
        head.next=root.next;
        root.pre=head;
        return link.next;
    }
    //返回字串
    private static String reverseLink(DoubleSignalLink link,String str){
        DoubleSignalLink head=link;
        char [] arr =new char[str.length()];
        int i=0;
        while (head!=null){
            arr[i]=head.chr;
            head=head.next;
            i++;
        }
       return new String(arr);
    }

}

執行結果