LeetCode习题汇总

àì夳堔傛蜴生んèń 2023-01-02 12:25 100阅读 0赞

<table> 
 <thead> 
  <tr> 
   <th>No</th> 
   <th>Title</th> 
   <th>Difficulty</th> 
   <th>Topic</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>1</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111597280" rel="nofollow">Two Sum</a></td> 
   <td>Easy</td> 
   <td>Array, Hash Table</td> 
  </tr> 
  <tr> 
   <td>2</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111602950" rel="nofollow">Add Two Numbers</a></td> 
   <td>Medium</td> 
   <td>Math, Linked List</td> 
  </tr> 
  <tr> 
   <td>3</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111713275" rel="nofollow">Longest Substring Without Repeating Characters</a></td> 
   <td>Medium</td> 
   <td>Hash Table, Two Pointers, String, Sliding Window</td> 
  </tr> 
  <tr> 
   <td>4</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111846213" rel="nofollow">Median of Two Sorted Arrays</a></td> 
   <td>Hard</td> 
   <td>Array, Binary Search, Divide and Conquer</td> 
  </tr> 
  <tr> 
   <td>5</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111935026" rel="nofollow">Longest Palindromic Substring</a></td> 
   <td>Medium</td> 
   <td>String, Dynamic Programming</td> 
  </tr> 
  <tr> 
   <td>6</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111977057" rel="nofollow">ZigZag Conversion</a></td> 
   <td>Medium</td> 
   <td>String</td> 
  </tr> 
  <tr> 
   <td>7</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112007198" rel="nofollow">Reverse Integer</a></td> 
   <td>Easy</td> 
   <td>Math</td> 
  </tr> 
  <tr> 
   <td>8</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112134729" rel="nofollow">String to Integer</a></td> 
   <td>Medium</td> 
   <td>Math, String</td> 
  </tr> 
  <tr> 
   <td>9</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112148476" rel="nofollow">Palindrome Number</a></td> 
   <td>Easy</td> 
   <td>Math</td> 
  </tr> 
  <tr> 
   <td>10</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112253252" rel="nofollow">Regular Expression Matching</a></td> 
   <td>Hard</td> 
   <td>String, Dynamic Programming, Backtracking</td> 
  </tr> 
  <tr> 
   <td>11</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111996393" rel="nofollow">Container With Most Water</a></td> 
   <td>Medium</td> 
   <td>Array, Two Pointers</td> 
  </tr> 
  <tr> 
   <td>12</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112001431" rel="nofollow">Integer to Roman</a></td> 
   <td>Medium</td> 
   <td>String, Math</td> 
  </tr> 
  <tr> 
   <td>13</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112167167" rel="nofollow">Roman to Integer</a></td> 
   <td>Easy</td> 
   <td>String, Math</td> 
  </tr> 
  <tr> 
   <td>14</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112167351" rel="nofollow">Longest Common Prefix</a></td> 
   <td>Easy</td> 
   <td>String</td> 
  </tr> 
  <tr> 
   <td>15</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112056667" rel="nofollow">3Sum</a></td> 
   <td>Medium</td> 
   <td>Array, Two Pointers</td> 
  </tr> 
  <tr> 
   <td>16</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112059185" rel="nofollow">3Sum Closest</a></td> 
   <td>Medium</td> 
   <td>Array, Two Pointers</td> 
  </tr> 
  <tr> 
   <td>17</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112022241" rel="nofollow">Letter Combinations of a Phone Number</a></td> 
   <td>Medium</td> 
   <td>String, Backtracking, Depth-first Search, Breadth-first Search, Recursion</td> 
  </tr> 
  <tr> 
   <td>18</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112130325" rel="nofollow">4Sum</a></td> 
   <td>Medium</td> 
   <td>Array, Hash Table, Two Pointers</td> 
  </tr> 
  <tr> 
   <td>19</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112059778" rel="nofollow">Remove Nth Node From End of List</a></td> 
   <td>Medium</td> 
   <td>Linked List, Two Pointers</td> 
  </tr> 
  <tr> 
   <td>20</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112193776" rel="nofollow">Valid Parentheses</a></td> 
   <td>Easy</td> 
   <td>String, Stack</td> 
  </tr> 
  <tr> 
   <td>21</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112557321" rel="nofollow">Merge Two Sorted Lists</a></td> 
   <td>Easy</td> 
   <td>Linked List, Recursion</td> 
  </tr> 
  <tr> 
   <td>22</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112597062" rel="nofollow">Generate Parentheses</a></td> 
   <td>Medium</td> 
   <td>String, Backtracking</td> 
  </tr> 
  <tr> 
   <td>23</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112598548" rel="nofollow">Merge k Sorted Lists</a></td> 
   <td>Hard</td> 
   <td>Linked List, Divide and Conquer, Heap</td> 
  </tr> 
  <tr> 
   <td>24</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112604724" rel="nofollow">Swap Nodes in Pairs</a></td> 
   <td>Medium</td> 
   <td>Linked List, Recursion</td> 
  </tr> 
  <tr> 
   <td>25</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112646489" rel="nofollow">Reverse Nodes in k-Group</a></td> 
   <td>Hard</td> 
   <td>Linked List</td> 
  </tr> 
  <tr> 
   <td>29</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112691247" rel="nofollow">Divide Two Integers</a></td> 
   <td>Medium</td> 
   <td>Math</td> 
  </tr> 
  <tr> 
   <td>33</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112399600" rel="nofollow">Search in Rotated Sorted Array</a></td> 
   <td>Medium</td> 
   <td>Binary Search, Array</td> 
  </tr> 
  <tr> 
   <td>37</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115350815" rel="nofollow">Sudoku Solver</a></td> 
   <td>Hard</td> 
   <td>Backtracking</td> 
  </tr> 
  <tr> 
   <td>39</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112467723" rel="nofollow">Combination Sum</a></td> 
   <td>Medium</td> 
   <td>Array, Backtracking</td> 
  </tr> 
  <tr> 
   <td>40</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112545593" rel="nofollow">Combination Sum II</a></td> 
   <td>Medium</td> 
   <td>Array, Backtracking</td> 
  </tr> 
  <tr> 
   <td>46</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115483022" rel="nofollow">Permutations</a></td> 
   <td>Medium</td> 
   <td>Backtracking</td> 
  </tr> 
  <tr> 
   <td>47</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115821021" rel="nofollow">Permutations II</a></td> 
   <td>Medium</td> 
   <td>Backtracking</td> 
  </tr> 
  <tr> 
   <td>50</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/114887917" rel="nofollow">Pow(x, n)</a></td> 
   <td>Medium</td> 
   <td>Math, Binary Search</td> 
  </tr> 
  <tr> 
   <td>51</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115183650" rel="nofollow">N-Queens</a></td> 
   <td>Hard</td> 
   <td>Backtracking</td> 
  </tr> 
  <tr> 
   <td>71</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115528863" rel="nofollow">Simplify Path</a></td> 
   <td>Medium</td> 
   <td>String, Stack</td> 
  </tr> 
  <tr> 
   <td>77</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112449837" rel="nofollow">Combinations</a></td> 
   <td>Medium</td> 
   <td>Backstracking</td> 
  </tr> 
  <tr> 
   <td>78</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115315615" rel="nofollow">Subsets</a></td> 
   <td>Medium</td> 
   <td>Array, Backtracking, Bit Manipulation</td> 
  </tr> 
  <tr> 
   <td>90</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115951724" rel="nofollow">Subsets II</a></td> 
   <td>Medium</td> 
   <td>Array, Backtracking</td> 
  </tr> 
  <tr> 
   <td>93</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115291721" rel="nofollow">Restore IP Addresses</a></td> 
   <td>Medium</td> 
   <td>String, Backtracking</td> 
  </tr> 
  <tr> 
   <td>124</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117485472" rel="nofollow">Binary Tree Maximum Path Sum</a></td> 
   <td>Hard</td> 
   <td>Tree, Depth-first Search, Recursion</td> 
  </tr> 
  <tr> 
   <td>131</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115278775" rel="nofollow">Palindrome Partitioning</a></td> 
   <td>Medium</td> 
   <td>Dynamic Programming, Backtracking, Depth-first Search</td> 
  </tr> 
  <tr> 
   <td>144</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117415552" rel="nofollow">Binary Tree Preorder Traversal</a></td> 
   <td>Easy</td> 
   <td>Stack, Tree</td> 
  </tr> 
  <tr> 
   <td>146</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115263747" rel="nofollow">LRU Cache</a></td> 
   <td>Medium</td> 
   <td>Design, Hash Table, Linked List</td> 
  </tr> 
  <tr> 
   <td>173</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117409397" rel="nofollow">Binary Search Tree Iterator</a></td> 
   <td>Medium</td> 
   <td>Stack, Tree, Design</td> 
  </tr> 
  <tr> 
   <td>203</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111731490" rel="nofollow">Remove Linked List Elements</a></td> 
   <td>Easy</td> 
   <td>Linked List</td> 
  </tr> 
  <tr> 
   <td>204</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111773775" rel="nofollow">Count Primes</a></td> 
   <td>Easy</td> 
   <td>Math, Hash Table</td> 
  </tr> 
  <tr> 
   <td>205</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111825420" rel="nofollow">Isomorphic Strings</a></td> 
   <td>Easy</td> 
   <td>Hash Table</td> 
  </tr> 
  <tr> 
   <td>206</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111772258" rel="nofollow">Reverse Linked List</a></td> 
   <td>Easy</td> 
   <td>Linked List</td> 
  </tr> 
  <tr> 
   <td>216</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112450619" rel="nofollow">Combination Sum III</a></td> 
   <td>Medium</td> 
   <td>Array, Backtracking</td> 
  </tr> 
  <tr> 
   <td>217</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111829319" rel="nofollow">Contains Duplicate</a></td> 
   <td>Easy</td> 
   <td>Array, Hash Table</td> 
  </tr> 
  <tr> 
   <td>219</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111871921" rel="nofollow">Contains Duplicate II</a></td> 
   <td>Easy</td> 
   <td>Array, Hash Table, Sliding Window</td> 
  </tr> 
  <tr> 
   <td>225</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112199414" rel="nofollow">Implement Stack using Queues</a></td> 
   <td>Easy</td> 
   <td>Stack, Design</td> 
  </tr> 
  <tr> 
   <td>226</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111875868" rel="nofollow">Invert Binary Tree</a></td> 
   <td>Easy</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>228</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112211436" rel="nofollow">Summary Ranges</a></td> 
   <td>Easy</td> 
   <td>Two Pointers, Array</td> 
  </tr> 
  <tr> 
   <td>230</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117377381" rel="nofollow">Kth Smallest Element in a BST</a></td> 
   <td>Medium</td> 
   <td>Binary Search, Tree</td> 
  </tr> 
  <tr> 
   <td>234</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112256599" rel="nofollow">Palindrome Linked List</a></td> 
   <td>Easy</td> 
   <td>Linked List, Two Pointers</td> 
  </tr> 
  <tr> 
   <td>237</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111747456" rel="nofollow">Delete Node in a Linked List</a></td> 
   <td>Easy</td> 
   <td>Linked List</td> 
  </tr> 
  <tr> 
   <td>242</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112915252" rel="nofollow">Valid Anagram</a></td> 
   <td>Easy</td> 
   <td>Sort, Hash Table</td> 
  </tr> 
  <tr> 
   <td>263</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112976174" rel="nofollow">Ugly Number</a></td> 
   <td>Easy</td> 
   <td>Math</td> 
  </tr> 
  <tr> 
   <td>264</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112982331" rel="nofollow">Ugly Number II</a></td> 
   <td>Medium</td> 
   <td>Math, Dynamic Programming, Heap</td> 
  </tr> 
  <tr> 
   <td>268</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112702812" rel="nofollow">Missing Number</a></td> 
   <td>Easy</td> 
   <td>Array, Math, Bit Manipulation</td> 
  </tr> 
  <tr> 
   <td>278</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/113047441" rel="nofollow">First Bad Version</a></td> 
   <td>Easy</td> 
   <td>Binary Search</td> 
  </tr> 
  <tr> 
   <td>283</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112961648" rel="nofollow">Move Zeroes</a></td> 
   <td>Easy</td> 
   <td>Array, Two Pointers</td> 
  </tr> 
  <tr> 
   <td>290</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/113697490" rel="nofollow">Word Pattern</a></td> 
   <td>Easy</td> 
   <td>Hash Table</td> 
  </tr> 
  <tr> 
   <td>292</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/113185752" rel="nofollow">Nim Game</a></td> 
   <td>Easy</td> 
   <td>Brainteaser,Minimax,Bit Manipulation</td> 
  </tr> 
  <tr> 
   <td>303</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/113702295" rel="nofollow">Range Sum Query - Immutable</a></td> 
   <td>Easy</td> 
   <td>Dynamic Programming</td> 
  </tr> 
  <tr> 
   <td>322</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/111938520" rel="nofollow">Coin Change</a></td> 
   <td>Medium</td> 
   <td>Dynamic Programming</td> 
  </tr> 
  <tr> 
   <td>326</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/113158559" rel="nofollow">Power of Three</a></td> 
   <td>Easy</td> 
   <td>Math</td> 
  </tr> 
  <tr> 
   <td>332</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115400311" rel="nofollow">Reconstruct Itinerary</a></td> 
   <td>Medium</td> 
   <td>Depth-first Search, Graph</td> 
  </tr> 
  <tr> 
   <td>345</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/113080584" rel="nofollow">Reverse Vowels of a String</a></td> 
   <td>Easy</td> 
   <td>Two Pointers, String</td> 
  </tr> 
  <tr> 
   <td>349</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112270481" rel="nofollow">Intersection of Two Arrays</a></td> 
   <td>Easy</td> 
   <td>Hash Table, Two Pointers, Binary Search, Sort</td> 
  </tr> 
  <tr> 
   <td>350</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/113065834" rel="nofollow">Intersection of Two Arrays II</a></td> 
   <td>Easy</td> 
   <td>Hash Table, Two Pointers, Binary Search, Sort</td> 
  </tr> 
  <tr> 
   <td>367</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/113101625" rel="nofollow">Valid Perfect Square</a></td> 
   <td>Easy</td> 
   <td>Binary Search, Math</td> 
  </tr> 
  <tr> 
   <td>374</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/113061920" rel="nofollow">Guess Number Higher or Lower</a></td> 
   <td>Easy</td> 
   <td>Binary Search</td> 
  </tr> 
  <tr> 
   <td>404</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117370783" rel="nofollow">Sum of Left Leaves</a></td> 
   <td>Easy</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>415</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/114345091" rel="nofollow">Add Strings</a></td> 
   <td>Easy</td> 
   <td>String</td> 
  </tr> 
  <tr> 
   <td>485</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115924200" rel="nofollow">Max Consecutive Ones</a></td> 
   <td>Easy</td> 
   <td>Array</td> 
  </tr> 
  <tr> 
   <td>501</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117270765" rel="nofollow">Find Mode in Binary Search Tree</a></td> 
   <td>Easy</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>504</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117309544" rel="nofollow">Base 7</a></td> 
   <td>Easy</td> 
   <td>Math</td> 
  </tr> 
  <tr> 
   <td>513</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117384321" rel="nofollow">Find Bottom Left Tree Value</a></td> 
   <td>Medium</td> 
   <td>Tree, Depth-first Search, Breadth-first Search</td> 
  </tr> 
  <tr> 
   <td>515</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117464343" rel="nofollow">Find Largest Value in Each Tree Row</a></td> 
   <td>Medium</td> 
   <td>Tree, Depth-first Search, Breadth-first Search</td> 
  </tr> 
  <tr> 
   <td>520</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117194701" rel="nofollow">Detect Capital</a></td> 
   <td>Easy</td> 
   <td>String</td> 
  </tr> 
  <tr> 
   <td>563</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/114716970" rel="nofollow">Binary Tree Tilt</a></td> 
   <td>Easy</td> 
   <td>Tree, Depth-first Search, Recursion</td> 
  </tr> 
  <tr> 
   <td>566</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117171082" rel="nofollow">Reshape the Matrix</a></td> 
   <td>Easy</td> 
   <td>Array</td> 
  </tr> 
  <tr> 
   <td>572</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117164627" rel="nofollow">Subtree of Another Tree</a></td> 
   <td>Easy</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>617</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/112827550" rel="nofollow">Merge Two Binary Trees</a></td> 
   <td>Easy</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>623</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117440497" rel="nofollow">Add One Row to Tree</a></td> 
   <td>Medium</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>637</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117377431" rel="nofollow">Average of Levels in Binary Tree</a></td> 
   <td>Easy</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>653</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115436499" rel="nofollow">Two Sum IV - Input is a BST</a></td> 
   <td>Easy</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>655</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117373791" rel="nofollow">Print Binary Tree</a></td> 
   <td>Medium</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>693</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115500462" rel="nofollow">Binary Number with Alternating Bits</a></td> 
   <td>Easy</td> 
   <td>Bit manipulation</td> 
  </tr> 
  <tr> 
   <td>696</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115468453" rel="nofollow">Count Binary Substrings</a></td> 
   <td>Easy</td> 
   <td>Tree</td> 
  </tr> 
  <tr> 
   <td>704</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115512322" rel="nofollow">Binary Search</a></td> 
   <td>Easy</td> 
   <td>Binary Search</td> 
  </tr> 
  <tr> 
   <td>938</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117326278" rel="nofollow">ange Sum of BST</a></td> 
   <td>Easy</td> 
   <td>Tree, Depth-first Search, Recursion</td> 
  </tr> 
  <tr> 
   <td>989</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/114370509" rel="nofollow">Add to Array-Form of Integer</a></td> 
   <td>Easy</td> 
   <td>Array</td> 
  </tr> 
  <tr> 
   <td>1143</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/114928943" rel="nofollow">Longest Common Subsequence</a></td> 
   <td>Medium</td> 
   <td>Dynamic Programming</td> 
  </tr> 
  <tr> 
   <td>1266</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/117302497" rel="nofollow">Minimum Time Visiting All Points</a></td> 
   <td>Easy</td> 
   <td>Array, Geometry</td> 
  </tr> 
  <tr> 
   <td>1732</td> 
   <td><a href="https://blog.csdn.net/u011863024/article/details/115534347" rel="nofollow">Find the Highest Altitude</a></td> 
   <td>Easy</td> 
   <td>Array</td> 
  </tr> 
 </tbody> 
</table>