Given a list of words, each word consists of English lowercase letters. Let's say word1 is a predecessor of word2 if and only if we can add exactly one letter anywhere in word1 to make it equal to word2.  For example, "abc" is a predecessor of &…

原题链接在这里:https://leetcode.com/problems/longest-string-chain/ 题目: Given a list of words, each word consists of English lowercase letters. Let's say word1 is a predecessor of word2 if and only if we can add exactly one letter anywhere in word1 to make i…

题目如下: Given a list of words, each word consists of English lowercase letters. Let's say word1 is a predecessor of word2 if and only if we can add exactly one letter anywhere in word1 to make it equal to word2.  For example, "abc" is a predecesso…

1048. Longest String Chain https://leetcode.com/problems/longest-string-chain/ Let's say word1 is a predecessor of word2 if and only if we can add exactly one letter anywhere in word1 to make it equal to word2.  For example, "abc" is a predecess…

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 is "bbbb". Example 2:Input:…

题目描述 Given a string, find the length of the longest substring without repeating characters. Example 1: Input: "abcabcbb" Output: 3 Explanation: The answer is "abc", with the length of 3. Example 2: Input: "bbbbb" Output: 1 Ex…

Given a string s, find the longest palindromic substring in s. You may assume that the maximum length of s is 1000. Example 1: Input: "babad" Output: "bab" Note: "aba" is also a valid answer. Example 2: Input: "cbbd"…

Given a string s , find the length of the longest substring t  that contains at most 2 distinct characters. Example 1: Input: "eceba" Output: 3 Explanation: tis "ece" which its length is 3. Example 2: Input: "ccaabbb" Output:…

Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring. Example 1: Input: "(()" Output: 2 Explanation: The longest valid parentheses substring is "()" Example…

Write a function to find the longest common prefix string amongst an array of strings. If there is no common prefix, return an empty string "". Example 1: Input: ["flower","flow","flight"] Output: "fl" Exa…