题目描述：

LeetCode 516. Longest Palindromic Subsequence

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 ...

LeetCode Weekly Contest 19是LeetCode举办的第二十四场正式周赛，共4道题目，比赛时长1.5小时。

比赛链接：https://leetcode.com/contest/leetcode-weekly-contest-19/

题解列表：

LeetCode 504. Base 7

LeetCode 513. Find Left Most Element

LeetCode 515. Find Largest Element in Each Row

LeetCode 493. Reverse Pairs

题目描述：

LeetCode 493. Reverse Pairs

Given an array nums, we call (i, j) an important reverse pair if i < j and nums[i] > 2*nums[j].

You need to return the number of important reverse pairs in the ...

题目描述：

LeetCode 515. Find Largest Element in Each Row

You need to find the largest value in each row of a binary tree.

Example:

Input: 

          1
         / \
        3   2
       / \   \  
      5   3   9 

Output: [1, 3, 9]

题目大意：

给定二叉树，返回其每一行的最大元素。

解题思路：

二叉树的层次遍历 ...

题目描述：

LeetCode 513. Find Left Most Element

Given a binary tree, find the leftmost value in the last row of the tree.

Example 1:

Input:

    2
   / \
  1   3

Output:
1

Example 2:

Input:

        1
       / \
      2   3
     /   / \
    4   5   6
       /
      7 ...