zhouworld16的专栏

第二章介绍了插入排序和归并排序，于是想到POJ上弄几道水题练下。排序的水题果断都好水，归并没有用哨兵，而是直接使用了2.3-2习题的方式，插入排序在查找位置的时候用的是2.3-6习题提到的二分查找。不过虽然是水题，但我是菜鸟水平，所以当看到高手用48K和0MS解决掉这些题后，真心觉得自己弱爆了。        水题号：2388；        归并：2388Ac

题目要求如下：Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, given n = 3, a solution set is:"((()))", "(()())", "(())()", "(

题目要求：Given a linked list, remove the nth node from the end of list and return its head.For example, Given linked list: 1->2->3->4->5, and n = 2. After removing the second node from the end,

题目要求如下：Given a digit string, return all possible letter combinations that the number could represent.A mapping of digit to letters (just like on the telephone buttons) is given below.Input:Dig

题目要求：Given n non-negative integers a1, a2, ...,an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of linei is at (i, ai) and (i

题目要求：The string "PAYPALISHIRING" is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)P A H NA

题目要求如下：Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would h

题目要求如下：Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note:Elements in

题目要求如下：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 longest palindromic substring.也就是传说中的求最长回文子

题目要求如下：Write a function to find the longest common prefix string amongst an array of strings.找出所有字符串的最长公共前缀。这道题很简单，但需要注意减少比较字符的操作次数。思路是这样的：2个字符串的最长公共前缀，其长度肯定不会超过最短的字符串的长度，设最短的字符串长度为n，那么只要比较这2个

题目要求：Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for "abcabcbb" is "abc", which the length is

题目要求：There are two sorted arrays A and B of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).如果使用像归并排序那样的归并方式，从头遍历A和B，比较A

题目要求：Reverse digits of an integer.Example1: x = 123, return 321Example2: x = -123, return -321Have you thought about this?Here are some good questions to ask before coding. Bonus points for

题目要求：mplement atoi to convert a string to an integer.Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible inpu

题目要求：Given an array of integers, find two numbers such that they add up to a specific target number.The function twoSum should return indices of the two numbers such that they add up to the target,

题目要求：You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as

题目要求：Determine whether an integer is a palindrome. Do this without extra space.Some hints:Could negative integers be palindromes? (ie, -1)If you are thinking of converting the integer to strin

题目要求如下：Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.The brackets must close in the correct order, "()" and "()[]{}"