本篇梳理「归并多个有序列表」问题。求和问题是指一类从数组中找出 K 个数满足其和为给定整数的问题。

本篇将「求和问题」梳理一遍。求和问题是指一类从数组中找出 K 个数满足其和为给定整数的问题。

Longest Common Prefix - LeetCode

Write a function to find the longest common prefix string amongst an array of strings.

本篇总结了两个使用「双指针」解决问题的方法。都达到了扫描一遍计算结果的效果，区别在于，一个是「相遇问题」，一个是「追及问题」。

Regular Expression Matching - LeetCode

Implement regular expression matching with support for '.' and '*'.

第5题和第9题都与「回文字符串」有关，且用到了经典的「动态规划」方法。在「最长回文串」问题中，Manacher 算法是一种技巧性极高的经典方法。

Longest Substring Without Repeating Characters - LeetCode

Given a string, find the length of the longest substring without repeating characters.
Examples:
Given "abcabcbb", the answer is "abc", which the length is 3.
Given "bbbbb", the answer is "b", with the length of 1.
Given "pwwkew", the answer is "wke", with the length of 3. Note that the answer must be a substring, "pwke" is a subsequence and not a substring.