409. Longest Palindrome use as many as char in odds add 1 if any odd exists 479. Largest Palindrome Product enumerate all situation from max to min 266. Palindrome Permutation only one odd count 267. Palindrome Permutation II

336. Palindrome Pairs

517 Super Washing Machines the least steps we need to eventually finish this process is determined by the peak of abs(cnt) (accumulative count of gain/lose array) and the max of “gain/lose” array. >For a single machine, necessary operations is to transfer dresses from one side to another until sum of both sides and itself reaches the average number. We can calculate (required dresses) - (contained dresses) of each side as L and R: L > 0 && R > 0: both sides lacks dresses, and we can only export one dress from current machines at a time, so result is abs(L) + abs® L < 0 && R < 0: both sides contains too many dresses, and we can import dresses from both sides at the same time, so result is max(abs(L), abs®) L < 0 && R > 0 or L >0 && R < 0: the side with a larger absolute value will import/export its extra dresses from/to current machine or other side, so result is max(abs(L), abs®)

692. Top K Frequent Words 2017-10-15 682. Baseball Game 2017-09-23 677. Map Sum Pairs 2017-09-23 647. Palindromic Substrings 2017-09-06 624. Maximum Distance in Arrays 2017-11-04 598. Range Addition II 2017-10-22 592. Fraction Addition and Subtraction 2017-10-22 566. Reshape the Matrix 2017-10-09 564. Find the Closest Palindrome 2017-09-06 532. K-diff Pairs in an Array 2017-09-04 529. Minesweepe 2017-09-06 518. Coin Change 2 2017-10-19 517. Super Washing Machines 2017-09-06 516. Longest Palindromic Subsequence 2017-09-05

516 Longest Palindromic Subsequence O(2^n) Brute force. If the two ends of a string are the same, then they must be included in the longest palindrome subsequence. Otherwise, both ends cannot be included in the longest palindrome subsequence. O(n^2) memo the result from left to right. also rewrite in dp fashion 508 Most Frequent Subtree Sum postOrder and check count