cindy_niu的专栏

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

题目：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 ta

题目：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 hav

题目：Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.

题目：Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999.w

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题目：The count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, ...1 is read off as "one 1" or 11.11 is read off as "two 1s" or 21.21 is rea

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题目：Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.If the last word does not exist, return 0.Note: 

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题目：Implement 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

题目：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 c

题目：Given an array and a value, remove all instances of that value in place and return the new length.The order of elements can be changed. It doesn't matter what you leave beyond the new lengt

题目：Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.For example,Given 1->2->3->3->4->4->5, return 1->2->5.Gi

题目：Given numRows, generate the first numRows of Pascal's triangle.For example, given numRows = 5,Return[ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1]]思路：

题目：Given a sorted linked list, delete all duplicates such that each element appear only once.For example,Given 1->1->2, return 1->2.Given 1->1->2->3->3, return 1->2->3.思路：Attenti

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题目：Given a non-negative number represented as an array of digits, plus one to the number.The digits are stored such that the most significant digit is at the head of the list.思路：Atte

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题目：Implement strStr().Returns the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.实现子字符串

题目：Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.The same repeated number may be chosen from C unlim

题目：Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T.Each number in C may only be used once in th

题目：Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree is symmetric: 1 / \ 2 2 / \ / \3 4 4 3

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题目：Given two binary strings, return their sum (also a binary string).For example,a = "11"b = "1"Return "100".思路：

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题目：Given a binary tree, determine if it is height-balanced.For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node ne

题目：Given two sorted integer arrays A and B, merge B into A as one sorted array.Note:You may assume that A has enough space (size that is greater or equal to m + n) to hold additional eleme

题目：Given a binary tree, find its minimum depth.The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.

题目：Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root).For example:Given binary tree {3,9,20,#,

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题目：Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level).For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9

题目：Given a list, rotate the list to the right by k places, where k is non-negative.For example:Given 1->2->3->4->5->NULL and k = 2,return 4->5->1->2->3->NULL.给出一个链表，和一个非负数k, 要求从链表尾节点开始

题目：Given preorder and inorder traversal of a tree, construct the binary tree.Note:You may assume that duplicates do not exist in the tree.Anwser 1: 递归法思路解析：这道题是树中比较有难度的题目，需要根据先序遍历和中序

题目：Given an array of strings, return all groups of strings that are anagrams.Note: All inputs will be in lower-case.For example:Input:　　["tea","and","ate","eat","den"]Output:  

题目：Given a string s, partition s such that every substring of the partition is a palindrome.Return all possible palindrome partitioning of s.For example, given s = "aab",Return [