題目：
Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring.
思路：
以每個點為基礎，尋找回文字符串，兩種情況，一種是形如aba，中心店兩邊是對稱的，長度為奇數，另一種是形如aa，長度為偶數。
package string;public class LongestPalindromicSubstring { public String longestPalindrome(String s) { int len = s.length(); String max = ""; for (int i = 0; i < len; ++i) { String res = getStr(s, len, i, i); if (res.length() > max.length()) max = res; if (i + 1 < len && s.charAt(i) == s.charAt(i + 1)) { res = getStr(s, len, i, i + 1); if (res.length() > max.length()) max = res; } } return max; } PRivate String getStr(String s, int len, int left, int right) { while (right < len && left >= 0 && s.charAt(left) == s.charAt(right)) { --left; ++right; } return s.substring(left + 1, right); } public static void main(String[] args) { // TODO Auto-generated method stub LongestPalindromicSubstring l = new LongestPalindromicSubstring(); System.out.println(l.longestPalindrome("aabbcc")); }}
新聞熱點
疑難解答
