似溦若岚

摘要： Flatten Binary Tree to Linked ListGiven 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: 1 \ 2 \ 3 \ 4 \ 5 \ ... 阅读全文

摘要： Populating Next Right Pointers in Each Node IIFollow up for problem "Populating Next Right Pointers in Each Node".What if the given tree could be any binary tree? Would your previous solution still work?Note:You may only use constant extra space.For example,Given the following binary tree, 阅读全文

摘要： Populating Next Right Pointers in Each NodeGiven a binary tree struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; }Populate each next pointer to point to its next right node. If there is no next right node, the next pointer should be set toNULL.In... 阅读全文

摘要： Pascal's Triangle IIGiven an indexk, return thekthrow of the Pascal's triangle.For example, givenk= 3,Return[1,3,3,1].Note:Could you optimize your algorithm to use onlyO(k) extra space?和118基本没区别吧…… 1 class Solution { 2 public: 3 vector getRow(int rowIndex) { 4 // Start typing your C/C++ ... 阅读全文

摘要： Pascal's TriangleGivennumRows, generate the firstnumRowsof Pascal's triangle.For example, givennumRows= 5,Return[ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1]]没啥好说的。。。 1 class Solution { 2 public: 3 vector > generate(int numRows) { 4 // Start typing your C/C++ solution below 5 ... 阅读全文

摘要： 1 class Solution { 2 public: 3 vector> findLadders(string start, string end, unordered_set &dict) { 4 // Start typing your C/C++ solution below 5 // DO NOT write int main() function 6 vector > result; 7 unordered_map > adj_set; 8 queue, int> > path; 9 ... 阅读全文

摘要： Word LadderGiven two words (startandend), and a dictionary, find the length of shortest transformation sequence fromstarttoend, such that:Only one letter can be changed at a timeEach intermediate word must exist in the dictionaryFor example,Given:start="hit"end="cog"dict=["h 阅读全文

摘要： Valid PalindromeGiven 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"isnota palindrome.Note:Have you consider that the string might be empty? This is a 阅读全文

摘要： Binary Tree Maximum Path SumGiven 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 3Return6.二叉树后序历遍的变形。 1 /** 2 * Definition for binary tree 3 * struct TreeNode { 4 * int val; 5 * ... 阅读全文