Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. Note: For the purpose of this problem, we define empty string as valid palindrome. Example 1: Input: "A man, a plan, a canal: Panama" O…
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome. Note:Have you consider that th…
题目: 有效回文串 给定一个字符串,判断其是否为一个回文串.只包含字母和数字,忽略大小写. 样例 "A man, a plan, a canal: Panama" 是一个回文. "race a car" 不是一个回文. 注意 你是否考虑过,字符串有可能是空字符串?这是面试过程中,面试官常常会问的问题. 在这个题目中,我们将空字符串判定为有效回文. 挑战 O(n) 时间复杂度,且不占用额外空间. 解题: 去除非有效字符后,整体是个回文串,两边查找,利用快速排序的思想,…
Given a string s, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation. Example 1: Input: "aacecaaa" Output: "aaacecaaa&quo…
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome. Note:Have you consider that th…
给定一个字符串,确定它是否是回文,只考虑字母数字字符和忽略大小写.例如:"A man, a plan, a canal: Panama" 是回文字符串."race a car" 不是回文字符串.注意:你有考虑过这个字符串可能是空的吗? 在面试中这是一个很好的问题.针对此题目,我们将空字符串定义为有效的回文字符串.详见:https://leetcode.com/problems/valid-palindrome/description/ Java实现: class S…
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example, "A man, a plan, a canal: Panama" is a palindrome. "race a car" is not a palindrome. Note: Have you consider that…
Problem Description Write a program to determine whether a word is a palindrome. A palindrome is a sequence of characters that is identical to the string when the characters are placed in reverse order. For example, the following strings are palindro…
Given a string S, you are allowed to convert it to a palindrome by adding characters in front of it. Find and return the shortest palindrome you can find by performing this transformation. For example: Given "aacecaaa", return "aaacecaaa&qu…
Easy! 题目描述: 给定一个字符串,验证它是否是回文串,只考虑字母和数字字符,可以忽略字母的大小写. 说明:本题中,我们将空字符串定义为有效的回文串. 示例 1: 输入: "A man, a plan, a canal: Panama" 输出: true 示例 2: 输入: "race a car" 输出: false 解题思路: 验证回文字符串是比较常见的问题,所谓回文,就是一个正读和反读都一样的字符串,比如“level”或者“noon”等等就是回文串.但是这…