LeetCode5.最长回文子串

class Solution {
    public String longestPalindrome(String s) {
        int n=s.length();
        int left=0;
        int right=0;
        boolean dp[][] = new boolean[n][n];

        // dp[i][j]=dp[i+1][j-1] && s[i]==s[j]
        for(int i=n-1;i>=0;i--){
            for(int j=i;j<n;j++){
                dp[i][j] = s.charAt(i)==s.charAt(j) && (j-i<2 || dp[i+1][j-1]);
                if(dp[i][j] && j-i+1 > right-left+1 ){
                    right=j;
                    left=i;
                }
            }
        }
        return s.substring(left,right+1);
    }
}

LeetCode1143.最长公共子序列

class Solution {
    public int longestCommonSubsequence(String text1, String text2) {
        if(text1==null || text1==null || text1.length()==0 || text2.length()==0)
            return 0;
        int m=text1.length(),n=text2.length();
        int [][] dp =new int[m+1][n+1];
        for(int i = 1;i<=m;i++){
            for(int j=1;j<=n;j++){
                if(text1.charAt(i-1)==text2.charAt(j-1))
                    dp[i][j]=dp[i-1][j-1]+1;
                else
                    dp[i][j]=Math.max(dp[i-1][j],dp[i][j-1]);
            }
        }
        return dp[m][n];
    }
}