Longest palindromic Substring

Longest palindromic Substring 

Given a string S, find the longest palindromic substring in s. The maximum length of S is assume, and there exists one unique longest palindromic substring.

Ideas:

The first thing I wanted to do was to get all the strings out of the way. I drew it on the back of the paper and thought of a way

Traverse the entire string I

1. If S.charat (i) = = S.charat (i + 1), with I and i+1 as the center to both sides of the expansion, if it is a palindrome and longer than the longest palindrome result has been obtained, update result

2. If S.charat (i-1) = = S.charat (i + 1), with i-1 and I + 1 centered on both sides of the expansion, if it is a palindrome and longer than the obtained palindrome result, update result

End of traversal returns result

1  Public classSolution {2      Publicstring Longestpalindrome (string s) {3         if(0 = = s.length () | | 1 = =s.length ())4             returns;5         Else{6String result = "";7             8              for(inti = 0; I < s.length (); i++){9                 if(i + 1 < s.length () && s.charat (i) = = S.charat (i + 1)) {//centered on I and i + 1Ten                     intj = i + 1; One                     intK =i; A //i = i; -                      while(k >= 0 && J < s.length ()) {//extend both sides of the center -                         if(S.charat (k) = =S.charat (j)) {         the                             if((j-k + 1) > Result.length ())//only bigger to update -result = S.substring (k, j + 1);//start index includes, end index does not include update longest palindrome -k--; -J + +; +                             Continue; -                         } +                          Break;//Both sides do not satisfy the direct exit A                     } at}//if -                 if(i-1 >= 0 && i + 1 < s.length () && s.charat (i-1) = = S.charat (i + 1)) {//Take I as the center -                     intj = i + 1; -                     intK = I-1; - //i = i-1; //extend both sides of the center -                      while(k >= 0 && J <s.length ()) { in                         if(S.charat (k) = =S.charat (j)) { -                             if((j-k + 1) >result.length ()) toresult = S.substring (k, j + 1); +k--; -J + +; the                             Continue; *}// while $                          Break;Panax Notoginseng                     } -                 } the             } +              A             returnresult; the         } +     } -}

Longest palindromic Substring