Given a string s, find the longest palindromic subsequence‘s length in s. You may assume that the maximum length of s is 1000.
Example 1:
Input:
"bbbab"
Output:
4
One possible longest palindromic subsequence is "bbbb".
Example 2:
Input:
"cbbd"
Output:
2
One possible longest palindromic subsequence is "bb".
这是一道典型的dp题，用dp[][]来存储i,j两个pointer指向的string的一个char, 分别按照相等和不相等来处理即可。
1 class Solution { 2 public int longestPalindromeSubseq(String s) { 3 int length = s.length(); 4 int[][] dp = new int[length][length]; 5 for (int i = 0; i < length; i++) { 6 dp[i][i] = 1; 7 } 8 for (int subLength = 2; subLength <= length; subLength++) { 9 for (int i = 0; i + subLength <= length; i++) { 10 int j = subLength + i - 1; 11 if (s.charAt(i) == s.charAt(j)) { 12 dp[i][j] = dp[i + 1][j - 1] + 2; 13 } else { 14 dp[i][j] = Math.max(dp[i + 1][j], dp[i][j - 1]); 15 } 16 } 17 } 18 return dp[0][length - 1]; 19 } 20 }
Longest Palindromic Subsequence
原文：https://www.cnblogs.com/beiyeqingteng/p/11029564.html