LeetCode刷题--点滴记录012

12. 剑指 Offer 58-II. 左旋转字符串

要求

字符串的左旋转操作是把字符串前面的若干个字符转移到字符串的尾部。请定义一个函数实现字符串左旋转操作的功能。比如，输入字符串"abcdefg"和数字2，该函数将返回左旋转两位得到的结果"cdefgab"。

解题

C++版本

#include 
using namespace std;

class Solution {
public:
	string reverseLeftWords01(string s, int n) { // 字符串切片
		return s.substr(n, s.size()) + s.substr(0, n);
	}
	string reverseLeftWords02(string s, int n) {
		reverse(s.begin(), s.begin() + n);
		reverse(s.begin() + n, s.end());
		reverse(s.begin(), s.end());
		return s;
	}

};

void test01()
{
	Solution solution;
	string s = "abcdefg";
	int n = 2;
	string rs1 = solution.reverseLeftWords01(s, n);
	cout << rs1 << endl;
	string rs2 = solution.reverseLeftWords02(s, n);
	cout << rs2 << endl;


}

int main()
{
	test01();

	system("pause");
	return 0;
}

Python版本

class Solution:
    def reverseLeftWords01(self, s, n): # 字符串切片
        return s[n:] + s[:n]
    
    def reverseLeftWords02(self, s, n): # 列表遍历拼接
        res = []
        for i in range(n, len(s)):
            res.append(s[i])
        for i in range(n):
            res.append(s[i])
        return ''.join(res)

def test01():
    solution = Solution()
    s = 'abcdefg'
    n = 2
    rs1 = solution.reverseLeftWords01(s,n)
    print(rs1)
    rs2 = solution.reverseLeftWords02(s,n)   
    print(rs2)     
if __name__=="__main__":
    test01()

Java版本

package com.hailei_01;

public class reverseLeftWords {
    public static void main(String[] args) {
        String s = "abcdefg";
        int n =2;
        String rs1 = reverseLeftWords01(s,2);
        System.out.println(rs1);
        String rs2 = reverseLeftWords02(s,2);
        System.out.println(rs2);

    }

    public static String reverseLeftWords01(String s, int n) {   // 字符串切片
        return s.substring(n, s.length()) + s.substring(0, n);
    }
    public static String reverseLeftWords02(String s, int n) {
        StringBuilder res = new StringBuilder();
        for(int i = n; i < s.length(); i++)
            res.append(s.charAt(i));
        for(int i = 0; i < n; i++)
            res.append(s.charAt(i));
        return res.toString();
    }

}

希望本文对大家有帮助，上文若有不妥之处，欢迎指正

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