面试题58 - II. 左旋转字符串

题目来源

leetcode

题目描述

题目解析

法1

class Solution {
    public String reverseLeftWords(String s, int n) {
       /* int c = n % s.length();
        if (c == 0){
            return s;
        }
			*/
			int c = n;
        for (int i = 0; i < c; i++){
            s = s + s.charAt(i);
        }
        
        return s.substring(c);
    }
}

法2

class Solution {
    public String reverseLeftWords(String s, int n) {
      /* int c = n % s.length();
        if (c == 0){
            return s;
        }
			*/
			int c = n;
			
        StringBuilder sb = new StringBuilder();

        for (int i = c; i < s.length(); i++){
            sb.append(s.charAt(i));
        }
        for (int i = 0; i < c; i++){
            sb.append(s.charAt(i));
        }



        return sb.toString();
    }
}

法3

    
    // 又当数组移动 s.length 出时回到原地
    public static String reverseLeftWords(String s, int n) {
       // 1 <= k < s.length <= 10000
        return s.substring(n) + s.substring(0, n);
    }