摘要： Best Time to Buy and Sell Stock Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to 阅读全文

摘要： Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longes 阅读全文

摘要： Palindrome Partitioning Given a string s, partition s such that every substring of the partition is a palindrome. Return all possible palindrome parti 阅读全文

摘要： Given a string S and a string T, count the number of distinct subsequences of T in S. A subsequence of a string is a new string which is formed from t 阅读全文

摘要： Given a binary tree, find the maximum path sum. The path may start and end at any node in the tree. For example:Given the below binary tree, 1 / \ 2 3 阅读全文

摘要： Given an unsorted array of integers, find the length of the longest consecutive elements sequence. For example,Given [100, 4, 200, 1, 3, 2],The longes 阅读全文

摘要： Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf path 1->2->3 whic 阅读全文

摘要： Reverse digits of an integer. Example1: x = 123, return 321Example2: x = -123, return -321 click to show spoilers. Have you thought about this? Here a 阅读全文

摘要： Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Pan 阅读全文

摘要： Determine whether an integer is a palindrome. Do this without extra space. click to show spoilers. Some hints: Could negative integers be palindromes? 阅读全文