459.md

459. Repeated Substring Pattern

Description

link

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Solution

• First char of input string is first char of repeated substring
• Last char of input string is last char of repeated substring
• Let S1 = S + S (where S in input string)
• Remove 1 and last char of S1. Let this be S2
• If S exists in S2 then return true else false
• Let i be index in S2 where S starts then repeated substring length i + 1 and repeated substring S[0: i+1]

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Code

O(1) O(1)

class Solution:
    def repeatedSubstringPattern(self, s: str) -> bool:
        if not str:
            return False
            
        ss = (s + s)[1:-1]
        return ss.find(s) != -1