代码：

class Solution {public int longestPalindromeSubseq(String s) {int n = s.length();int[][] dp = new int[n][n];for(int i=n-1;i>=0;i--){dp[i][i] = 1;char c1 = s.charAt(i);for(int j=i+1;j<n;j++){char c2 = s.charAt(j);if(c1==c2){dp[i][j] = dp[i+1][j-1]+2;}else{dp[i][j] = Math.max(dp[i+1][j],dp[i][j-1]);}}}return dp[0][n-1];}
}