momentforver的专栏

原题如下：Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.For example,Given:s1 = "aabcc",s2 = "dbbca",When s3 = "aadbbcbcac", return true.When s3 = "aadbb

原题如下：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

原题如下：Given a collection of intervals, merge all overlapping intervals.For example,Given [1,3],[2,6],[8,10],[15,18],return [1,6],[8,10],[15,18].关键还是思路，当理解了

原题如下：Given a singly linked list L: L0→L1→…→Ln-1→Ln,reorder it to: L0→Ln→L1→Ln-1→L2→Ln-2→…You must do this in-place without altering the nodes' values.For example,Given {1,2,3,4}, reo

原题如下：Given a binary tree, flatten it to a linked list in-place.For example,Given 1 / \ 2 5 / \ \ 3 4 6The flattened tree should look like

原题如下：Reverse a linked list from position m to n. Do it in-place and in one-pass.For example:Given 1->2->3->4->5->NULL, m = 2 and n = 4,return 1->4->3->2->5->NULL.Note:Given m, 

原题如下：Two elements of a binary search tree (BST) are swapped by mistake.Recover the tree without changing its structure.Note:A solution using O(n) space is pretty straight forward. Coul

Best Time to Buy and Sell Stock的原题如下：

Jump Game的原题如下：Given an array of non-negative integers, you are initially positioned at the first index of the array.Each element in the array represents your maximum jump length at that pos

这道题的暴力解法比较简单，

Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.)You have the following 3 operations permitted on a word:

Implement strStr().Returns a pointer to the first occurrence of needle in haystack, or null if needle is not part of haystack.

原题如下：Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and return its area.此题s

原题如下：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 i

原题如下：Given an array of strings, return all groups of strings that are anagrams.不得不说，这道题的题意太模糊了，

原题如下：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 N

原题如下：Given a linked list, reverse the nodes of a linked list k at a time and return its modified list.If the number of nodes is not a multiple of k then left-out nodes in the end should rema

原题如下：Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity.思路一：按照归并排序的思路

原题如下：Sort a linked list in O(n log n) time using constant space complexity.leetcode上

原题如下：Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.Below is one possible representation of s1 = "great": great /

原题如下：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.思路：

原题如下：Given a set of distinct integers, S, return all possible subsets.Note:Elements in a subset must be in non-descending order.The solution set must not contain duplicate subsets.

原题如下：A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.Return a deep copy of the list.

原题如下：Given an input string, reverse the string word by word.For example,Given s = "the sky is blue",return "blue is sky the".这道题的题意很明确，首先想到的是将字符串按空格分割

原题如下：Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.For example, givens = "leetcode",dic

原题如下：The set [1,2,3,…,n] contains a total of n! unique permutations.By listing and labeling all of the permutations in order,We get the following sequence (ie, for n = 3):"123""132""

原题如下：Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.Above is a histogram wh

Roman to Integer 的原题如下：

原题如下：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)).这道题muqian

原题如下：

原题如下：Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.OJ's undirected graph serialization:Nodes are labeled uniquely.We use # as a separ

原题如下：Implement int sqrt(int x).Compute and return the square root of x.普通遍历方法kendi

原题如下：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

原题如下：Given an unsorted integer array, find the first missing positive integer.For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2.Your algorithm should run in O(n) time and us

原题如下：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.这道题关键是理解题意，

原题如下：Evaluate the value of an arithmetic expression in Reverse Polish Notation.Valid operators are +, -, *, /. Each operand may be an integer or another expression.Some examples:

有一周没更新博客了，过去的一周打击太大

原题如下：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 the original string by deleting some

原题如下：Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST.之前有一个将顺序存储的vectorbianhuan

紧接上篇的3Sun问题，4Sum问题的描述如下：Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array which gives the sum of