LeetCode—Interview question: string rotation (violence + splicing)

String rotation (simple)

September 26, 2020

Question source: Likou

Problem solving

• Violence
  simulates rotation, and returns true if it is right, the speed is too slow

class Solution {
    
    
    public boolean isFlipedString(String s1, String s2) {
    
    
        if(s1.length()!=s2.length()) return false;
        if(s1.length()==0 && s2.length()==0) return true;
        for(int i=0;i<s1.length();i++){
    
    
            if(s1.charAt(i)==s2.charAt(0)){
    
    
                if((s1.substring(i,s1.length())+s1.substring(0,i)).equals(s2)) return true;
            }
        }
        return false;
    }
}

• Splicing
  Use s2 for self-stitching. If s2 is rotated by s1, there must be an s1 in s2+s2

class Solution {
    
    
    public boolean isFlipedString(String s1, String s2) {
    
    
        if(s1.length()!=s2.length()) return false;
        return (s2+s2).indexOf(s1)!=-1;
    }
}