392. Is Subsequence Given a string s and a string t, check if s is subsequence of t. You may assume that there is only lower case English letters in both s and t. t is potentially a very long (length ~= 500,000) string, and s is a short string (<=100…

这是悦乐书的第270次更新,第284篇原创 01 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第136题(顺位题号是594).我们定义一个和谐数组是一个数组,其最大值和最小值之间的差值恰好为1.给定一个整数数组,在其所有可能的子序列中找到其最长的和谐子序列的长度.例如: 输入:[1,3,2,2,5,2,3,7] 输出:5 说明:最长的和谐子序列是[3,2,2,2,3]. 注意:输入数组的长度不会超过20,000. 本次解题使用的开发工具是eclipse,jdk使用的版本是1.8…

这是悦乐书的第252次更新,第265篇原创 01 看题和准备 今天介绍的是LeetCode算法题中Easy级别的第119题(顺位题号是521).给定一组两个字符串,您需要找到这组两个字符串中最长的不同子序列.最长的不同子序列被定义为这些字符串之一的最长子序列,并且此子序列不应该是其他字符串的任何子序列. 子序列是可以通过删除一些字符而不改变其余元素的顺序从一个序列导出的序列.任何字符串都是其自身的子序列,空字符串是任何字符串的子序列.输入将是两个字符串,输出需要是最长的不同子序列的长度.如果最长…

问题描述 You need to find the largest element in each row of a Binary Tree. Example: Input: 1 / \ 2 3 / \ \ 5 3 9 Output: [1, 3, 9] 算法分析 使用两个队列,逐层遍历二叉树的各个节点,每个队列中的节点都是同一层的节点,在遍历一层时,找出该层最大的节点值加入ArrayList中. Java算法实现: /** * Definition for a binary tree node…

问题描述 Given a binary tree, find the left most element 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 Output: 7 Note: You may assume the tree is not NULL. 算法分析: 逐层遍历二叉树是很经典的算法,常规的逐层遍历二叉树是使…

395. Longest Substring with At least K Repeating Characters Find the length of the longest substring T of a given string (consists of lowercase letters only) such that every character in T appears no less than k times. Example 1: Input: s = "aaabb&qu…

394. Decode String Given an encoded string, return it's decoded string. The encoding rule is: k[encoded_string], where the encoded_string inside the square brackets is being repeated exactly k times. Note that k is guaranteed to be a positive integer…

393. UTF-8 Validation A character in UTF8 can be from 1 to 4 bytes long, subjected to the following rules: For 1-byte character, the first bit is a 0, followed by its unicode code. For n-bytes character, the first n-bits are all one's, the n+1 bit is…

#391. Perfect Rectangle Given N axis-aligned rectangles where N > 0, determine if they all together form an exact cover of a rectangular region. Each rectangle is represented as a bottom-left point and a top-right point. For example, a unit square is…

# 390. Elimination Game There is a list of sorted integers from 1 to n. Starting from left to right, remove the first number and every other number afterward until you reach the end of the list. Repeat the previous step again, but this time from righ…