4 Palindrome

abba 这是parlindrome， abab跟abba是anagram

266 Palindrome Permuation

5 Longest Palindromic Substring (L200)

647 Palindromic Substrings

516 Longest Palindromic Subsequence

730 Count Different Palindromic Subsequences （palindrome DP的最高境界）这里是求没重复的，另外在geeksforgeeks上看到了一种是有重复的

1332 Remove Palindromic Subsequences

409 Longest Palindrome

680 Valid Palindrome II

1216 Valid Palindrome III

336 Palindrome Pairs