README_EN.md

01.09. String Rotation

中文文档

Description

Given two strings, s1 and s2, write code to check if s2 is a rotation of s1 (e.g.,"waterbottle" is a rotation of"erbottlewat"). Can you use only one call to the method that checks if one word is a substring of another?

Example 1:

Input: s1 = "waterbottle", s2 = "erbottlewat"

Output: True

Example 2:

Input: s1 = "aa", "aba"

Output: False

 

Note:

1. 0 <= s1.length, s1.length <= 100000

Solutions

Python3

class Solution:
    def isFlipedString(self, s1: str, s2: str) -> bool:
        return len(s1) == len(s2) and s2 in s1 * 2

Java

class Solution {
    public boolean isFlipedString(String s1, String s2) {
        return s1.length() == s2.length() && (s1 + s1).contains(s2);
    }
}

C++

class Solution {
public:
    bool isFlipedString(string s1, string s2) {
        return s1.size() == s2.size() && (s1 + s1).find(s2) != string::npos;
    }
};

Go

func isFlipedString(s1 string, s2 string) bool {
	return len(s1) == len(s2) && strings.Contains(s1+s1, s2)
}

TypeScript

function isFlipedString(s1: string, s2: string): boolean {
    return s1.length === s2.length && (s2 + s2).indexOf(s1) !== -1;
}

Rust

impl Solution {
    pub fn is_fliped_string(s1: String, s2: String) -> bool {
        s1.len() == s2.len() && (s2.clone() + &s2).contains(&s1)
    }
}

impl Solution {
    pub fn is_fliped_string(s1: String, s2: String) -> bool {
        if s1 == s2 {
            return true;
        }
        if s1.len() != s2.len() {
            return false;
        }
        let s2: Vec<char> = (s2.clone() + &s2).chars().collect();
        let n = s1.len();
        let m = s2.len();
        for i in 0..m - n {
            let mut is_pass = true;
            for (j, c) in s1.chars().enumerate() {
                if c != s2[i + j] {
                    is_pass = false;
                    break;
                }
            }
            if is_pass {
                return true;
            };
        }
        false
    }
}

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