leetcode400

2021-10-06 05:43:14 -0700
Array
题号 题目链接 说明
基础
27 Remove Element
26 Remove Duplicates from Sorted Array
80 Remove Duplicates from Sorted Array II
277 Find the Celebrity
189 Rotate Array
41 First Missing Positive
299 Bulls and Cows
134 Gas Station
118 Pascal's Triangle 很少考
119 Pascal's Triangle II 很少考
169 Majority Element 很少考
229 Majority Element II 很少考
274 H-Index
275 H-Index II Binary Search
243 Shortest Word Distance
244 Shortest Word Distance II
245 Shortest Word Distance III
217 Contains Duplicate
219 Contains Duplicate II 很少考
220 Contains Duplicate III 很少考
55 Jump Game
45 Jump Game II
121 Best Time to Buy and Sell Stock
122 Best Time to Buy and Sell Stock II
123 Best Time to Buy and Sell Stock III
188 Best Time to Buy and Sell Stock IV
309 Best Time to Buy and Sell Stock with Cooldown
11 Container With Most Water
42 Trapping Rain Water
334 Increasing Triplet Subsequence
128 Longest Consecutive Sequence
164 Maximum Gap Bucket
287 Find the Duplicate Number
135 Candy 很少考
330 Patching Array 很少考
提高
4 Median of Two Sorted Arrays 很少考
321 Create Maximum Number 很少考
327 Count of Range Sum
289 Game of Life
Interval
57 Insert Interval
56 Merge Intervals
252 Meeting Rooms
253 Meeting Rooms II
352 Data Stream as Disjoint Intervals TreeMap
Counter
239 Sliding Window Maximum
295 Find Median from Data Stream
53 Maximum Subarray
325 Maximum Size Subarray Sum Equals k
209 Minimum Size Subarray Sum
238 Product of Array Except Self
152 Maximum Product Subarray
228 Summary Ranges
163 Missing Ranges
Counter
88 Merge Sorted Array
75 Sort Colors
283 Move Zeroes
376 Wiggle Subsequence
280 Wiggle Sort
324 Wiggle Sort II
278 First Bad Version
35 Search Insert Position
33 Search in Rotated Sorted Array
81 Search in Rotated Sorted Array II
153 Find Minimum in Rotated Sorted Array
154 Find Minimum in Rotated Sorted Array II
162 Find Peak Element
374 Guess Number Higher or Lower
34 Find First and Last Position of Element in Sorted Array
349 Intersection of Two Arrays
350 Intersection of Two Arrays II
315 Count of Smaller Numbers After Self
300 Longest Increasing Subsequence
354 Russian Doll Envelopes
String
题号 题目链接 说明
基础
28 Implement strStr()
14 Longest Common Prefix
58 Length of Last Word
387 First Unique Character in a String
383 Ransom Note
344 Reverse String
151 Reverse Words in a String
186 Reverse Words in a String II
345 Reverse Vowels of a String
205 Isomorphic Strings
293 Flip Game
294 Flip Game II
290 Word Pattern
242 Valid Anagram
49 Group Anagrams
249 Group Shifted Strings
87 Scramble String
179 Largest Number 很少考
6 ZigZag Conversion 很少考
161 One Edit Distance
38 Count and Say
358 Rearrange String k Distance Apart
316 Remove Duplicate Letters
271 Encode and Decode Strings
168 Excel Sheet Column Title
171 Excel Sheet Column Number
13 Roman to Integer
12 Integer to Roman
273 Integer to English Words
246 Strobogrammatic Number
247 Strobogrammatic Number II
248 Strobogrammatic Number III 很少考
提高
157 Read N Characters Given Read4
158 Read N Characters Given Read4 II - Call multiple times
68 Text Justification
65 Valid Number
Substring
76 Minimum Window Substring Sliding Window
30 Substring with Concatenation of All Words Sliding Window
3 Longest Substring Without Repeating Characters Sliding Window
340 Longest Substring with At Most K Distinct Characters Sliding Window
395 Longest Substring with At Least K Repeating Characters Sliding Window
159 Longest Substring with At Most Two Distinct Characters Sliding Window
Palindrome
125 Valid Palindrome
266 Palindrome Permutation
5 Longest Palindromic Substring
9 Palindrome Number
214 Shortest Palindrome
336 Palindrome Pairs
131 Palindrome Partitioning
132 Palindrome Partitioning II
267 Palindrome Permutation II
Parentheses
20 Valid Parentheses
22 Generate Parentheses
32 Longest Valid Parentheses
241 Different Ways to Add Parentheses
301 Remove Invalid Parentheses
Subsequence
392 Is Subsequence
115 Distinct Subsequences
187 Repeated DNA Sequences 很少考
Math
题号 题目链接
基础
7 Reverse Integer
165 Compare Version Numbers
66 Plus One
8 String to Integer (atoi)
258 Add Digits
67 Add Binary
43 Multiply Strings
29 Divide Two Integers
69 Sqrt(x)
50 Pow(x, n)
367 Valid Perfect Square
365 Water and Jug Problem
204 Count Primes
Sum
1 Two Sum
167 Two Sum II - Input array is sorted
15 3Sum
16 3Sum Closest 很少考
259 3Sum Smaller 很少考
18 4Sum
很少考
231 Power of Two
326 Power of Three
342 Power of Four
372 Super Pow
233 Number of Digit One
319 Bulb Switcher
292 Nim Game
202 Happy Number
400 Nth Digit
263 Ugly Number
264 Ugly Number II
306 Additive Number
172 Factorial Trailing Zeroes
343 Integer Break
396 Rotate Function
390 Elimination Game
386 Lexicographical Numbers
357 Count Numbers with Unique Digits
360 Sort Transformed Array
397 Integer Replacement
368 Largest Divisible Subset
Tree
题号 题目链接
基础
144 Binary Tree Preorder Traversal
94 Binary Tree Inorder Traversal
145 Binary Tree Postorder Traversal
102 Binary Tree Level Order Traversal
Preorder
100 Same Tree
101 Symmetric Tree
226 Invert Binary Tree preorder + BFS
257 Binary Tree Paths
112 Path Sum
113 Path Sum II
129 Sum Root to Leaf Numbers
298 Binary Tree Longest Consecutive Sequence
111 Minimum Depth of Binary Tree
Preorder
104 Maximum Depth of Binary Tree
110 Balanced Binary Tree
124 Binary Tree Maximum Path Sum
250 Count Univalue Subtrees
366 Find Leaves of Binary Tree
337 House Robber III postorder + preorder
BFS
107 Binary Tree Level Order Traversal II
103 Binary Tree Zigzag Level Order Traversal
199 Binary Tree Right Side View BFS + preorder
BST
98 Validate Binary Search Tree preorder
235 Lowest Common Ancestor of a Binary Search Tree preorder
236 Lowest Common Ancestor of a Binary Tree postorder
108 Convert Sorted Array to Binary Search Tree binary search
109 Convert Sorted List to Binary Search Tree binary search
173 Binary Search Tree Iterator inorder
230 Kth Smallest Element in a BST inorder
297 Serialize and Deserialize Binary Tree BFS
285 Inorder Successor in BST inorder
270 Closest Binary Search Tree Value preorder
272 Closest Binary Search Tree Value II inorder
99 Recover Binary Search Tree inorder
重要程度
156 Binary Tree Upside Down 很少考
114 Flatten Binary Tree to Linked List 很少考
255 Verify Preorder Sequence in Binary Search Tree 很少考
333 Largest BST Subtree 很少考
222 Count Complete Tree Nodes 很少考
105 Construct Binary Tree from Preorder and Inorder Traversal 很少考
106 Construct Binary Tree from Inorder and Postorder Traversal 很少考
116 Populating Next Right Pointers in Each Node 重要
117 Populating Next Right Pointers in Each Node II 重要
314 Binary Tree Vertical Order Traversal 重要
96 Unique Binary Search Trees 重要
95 Unique Binary Search Trees II 很少考
331 Verify Preorder Serialization of a Binary Tree 很少考
Topological Sort
题号 题目链接
207 Course Schedule
210 Course Schedule II
269 Alien Dictionary
Graph
题号 题目链接
基础
133 Clone Graph
399 Evaluate Division
310 Minimum Height Trees
图形学
149 Max Points on a Line
335 Self Crossing 很少考
356 Line Reflection 很少考
391 Perfect Rectangle 很少考
223 Rectangle Area 很少考
划分说明
此表是针对 Data Science 这个职位，对Leetcode前400题进行精简，划分精简规则如下：
  • 删除DS不常考，面试低频出现题目
  • 删除SDE考，过难题目
  • 删除高级数据结构算法，保留基础简单题目
  • 保留基础练手题目，提高代码能力

所有题目我们尽量保证客观公正，只是按大概率删除，目的是为了减轻DS的刷题负担。

适用人群：Data Science 职位相关人员

划分说明
这个重点题目是把Leetcode前400题进行精简，划分精简规则如下：
  • 删除不常考，面试低频出现题目
  • 删除重复代码题目（例：链表反转206题，代码在234题出现过）
  • 删除过于简单题目（例：100题：Same Tree）
  • 删除题意不同，代码基本相同题目（例：136 & 389，保留一个）

所有题目尽量保证客观公正，只是按大概率删除不常考题目，很多题目面经出现过， 但出现次数属于个位数或者只有一两家出现进行删除。所以如在面试中出现删除题目概不负责，这只是从概率上删除低频，简单题目。 旨在减轻大家的刷题负担，从400题减少到250题。

适用人群：有一定刷题基础，算法基础，二刷人群。

建议：400题全部刷完，再精刷这250题。
Leetcode 前 400 重点 250 题
题号 题目名称
1 Two Sum
3 Longest Substring Without Repeating Characters
4 Median of Two Sorted Arrays
5 Longest Palindromic Substring
7 Reverse Integer
8 String to Integer (atoi)
10 Regular Expression Matching
11 Container With Most Water
12 Integer to Roman
13 Roman to Integer
15 3Sum
17 Letter Combinations of a Phone Number
18 4Sum
20 Valid Parentheses
22 Generate Parentheses
23 Merge k Sorted Lists
26 Remove Duplicates from Sorted Array
27 Remove Element
28 Implement strStr()
29 Divide Two Integers
31 Next Permutation
32 Longest Valid Parentheses
33 Search in Rotated Sorted Array
34 Find First and Last Position of Element in Sorted Array
35 Search Insert Position
36 Valid Sudoku
37 Sudoku Solver
38 Count and Say
39 Combination Sum
40 Combination Sum II
41 First Missing Positive
42 Trapping Rain Water
43 Multiply Strings
44 Wildcard Matching
45 Jump Game II
46 Permutations
47 Permutations II
48 Rotate Image
49 Group Anagrams
50 Pow(x, n)
51 N-Queens
52 N-Queens II
53 Maximum Subarray
54 Spiral Matrix
55 Jump Game
56 Merge Intervals
57 Insert Interval
59 Spiral Matrix II
60 Permutation Sequence
62 Unique Paths
64 Minimum Path Sum
65 Valid Number
66 Plus One
67 Add Binary
68 Text Justification
69 Sqrt(x)
70 Climbing Stairs
71 Simplify Path
72 Edit Distance
74 Search a 2D Matrix
75 Sort Colors
76 Minimum Window Substring
77 Combinations
78 Subsets
79 Word Search
80 Remove Duplicates from Sorted Array II
81 Search in Rotated Sorted Array II
82 Remove Duplicates from Sorted List II
84 Largest Rectangle in Histogram
85 Maximal Rectangle
88 Merge Sorted Array
90 Subsets II
91 Decode Ways
96 Unique Binary Search Trees
98 Validate Binary Search Tree
101 Symmetric Tree
104 Maximum Depth of Binary Tree
108 Convert Sorted Array to Binary Search Tree
110 Balanced Binary Tree
111 Minimum Depth of Binary Tree
112 Path Sum
113 Path Sum II
115 Distinct Subsequences
116 Populating Next Right Pointers in Each Node
117 Populating Next Right Pointers in Each Node II
121 Best Time to Buy and Sell Stock
122 Best Time to Buy and Sell Stock II
123 Best Time to Buy and Sell Stock III
124 Binary Tree Maximum Path Sum
125 Valid Palindrome
126 Word Ladder II
127 Word Ladder
128 Longest Consecutive Sequence
130 Surrounded Regions
133 Clone Graph
134 Gas Station
138 Copy List with Random Pointer
139 Word Break
140 Word Break II
142 Linked List Cycle II
146 LRU Cache
149 Max Points on a Line
150 Evaluate Reverse Polish Notation
152 Maximum Product Subarray
153 Find Minimum in Rotated Sorted Array
154 Find Minimum in Rotated Sorted Array II
155 Min Stack
157 Read N Characters Given Read4
158 Read N Characters Given Read4 II - Call multiple times
161 One Edit Distance
162 Find Peak Element
163 Missing Ranges
168 Excel Sheet Column Title
171 Excel Sheet Column Number
173 Binary Search Tree Iterator
174 Dungeon Game
186 Reverse Words in a String II
188 Best Time to Buy and Sell Stock IV
189 Rotate Array
191 Number of 1 Bits
198 House Robber
200 Number of Islands
201 Bitwise AND of Numbers Range
202 Happy Number
204 Count Primes
205 Isomorphic Strings
207 Course Schedule
208 Implement Trie (Prefix Tree)
209 Minimum Size Subarray Sum
210 Course Schedule II
211 Add and Search Word - Data structure design
212 Word Search II
213 House Robber II
214 Shortest Palindrome
215 Kth Largest Element in an Array
216 Combination Sum III
217 Contains Duplicate
218 The Skyline Problem
219 Contains Duplicate II
220 Contains Duplicate III
221 Maximal Square
224 Basic Calculator
225 Implement Stack using Queues
226 Invert Binary Tree
227 Basic Calculator II
228 Summary Ranges
230 Kth Smallest Element in a BST
231 Power of Two
232 Implement Queue using Stacks
235 Lowest Common Ancestor of a Binary Search Tree
236 Lowest Common Ancestor of a Binary Tree
238 Product of Array Except Self
239 Sliding Window Maximum
240 Search a 2D Matrix II
241 Different Ways to Add Parentheses
242 Valid Anagram
244 Shortest Word Distance II
245 Shortest Word Distance III
249 Group Shifted Strings
251 Flatten 2D Vector
252 Meeting Rooms
253 Meeting Rooms II
254 Factor Combinations
256 Paint House
257 Binary Tree Paths
261 Graph Valid Tree
263 Ugly Number
264 Ugly Number II
265 Paint House II
268 Missing Number
269 Alien Dictionary
270 Closest Binary Search Tree Value
271 Encode and Decode Strings
273 Integer to English Words
274 H-Index
275 H-Index II
276 Paint Fence
277 Find the Celebrity
278 First Bad Version
279 Perfect Squares
280 Wiggle Sort
282 Expression Add Operators
283 Move Zeroes
284 Peeking Iterator
285 Inorder Successor in BST
286 Walls and Gates
287 Find the Duplicate Number
288 Unique Word Abbreviation
289 Game of Life
290 Word Pattern
291 Word Pattern II
293 Flip Game
294 Flip Game II
295 Find Median from Data Stream
296 Best Meeting Point
297 Serialize and Deserialize Binary Tree
298 Binary Tree Longest Consecutive Sequence
299 Bulls and Cows
300 Longest Increasing Subsequence
301 Remove Invalid Parentheses
302 Smallest Rectangle Enclosing Black Pixels
305 Number of Islands II
307 Range Sum Query - Mutable
308 Range Sum Query 2D - Mutable
309 Best Time to Buy and Sell Stock with Cooldown
311 Sparse Matrix Multiplication
312 Burst Balloons
314 Binary Tree Vertical Order Traversal
316 Remove Duplicate Letters
317 Shortest Distance from All Buildings
318 Maximum Product of Word Lengths
322 Coin Change
323 Number of Connected Components in an Undirected Graph
324 Wiggle Sort II
325 Maximum Size Subarray Sum Equals k
329 Longest Increasing Path in a Matrix
334 Increasing Triplet Subsequence
336 Palindrome Pairs
337 House Robber III
338 Counting Bits
339 Nested List Weight Sum
340 Longest Substring with At Most K Distinct Characters
341 Flatten Nested List Iterator
346 Moving Average from Data Stream
347 Top K Frequent Elements
348 Design Tic-Tac-Toe
350 Intersection of Two Arrays II
351 Android Unlock Patterns
352 Data Stream as Disjoint Intervals
353 Design Snake Game
354 Russian Doll Envelopes
355 Design Twitter
359 Logger Rate Limiter
361 Bomb Enemy
362 Design Hit Counter
364 Nested List Weight Sum II
367 Valid Perfect Square
374 Guess Number Higher or Lower
375 Guess Number Higher or Lower II
376 Wiggle Subsequence
377 Combination Sum IV
378 Kth Smallest Element in a Sorted Matrix
379 Design Phone Directory
380 Insert Delete GetRandom O(1)
381 Insert Delete GetRandom O(1) - Duplicates allowed
384 Shuffle an Array
385 Mini Parser
389 Find the Difference
394 Decode String
398 Random Pick Index
Data Science Leetcode 精简版
题号 题目名称
1 Two Sum
2 Add Two Numbers
3 Longest Substring Without Repeating Characters
5 Longest Palindromic Substring
7 Reverse Integer
8 String to Integer (atoi)
9 Palindrome Number
11 Container With Most Water
14 Longest Common Prefix
15 3Sum
16 3Sum Closest
17 Letter Combinations of a Phone Number
18 4Sum
19 Remove Nth Node From End of List
20 Valid Parentheses
21 Merge Two Sorted Lists
22 Generate Parentheses
24 Swap Nodes in Pairs
25 Reverse Nodes in k-Group
26 Remove Duplicates from Sorted Array
27 Remove Element
28 Implement strStr()
29 Divide Two Integers
30 Substring with Concatenation of All Words
32 Longest Valid Parentheses
33 Search in Rotated Sorted Array
35 Search Insert Position
36 Valid Sudoku
39 Combination Sum
40 Combination Sum II
41 First Missing Positive
42 Trapping Rain Water
45 Jump Game II
46 Permutations
47 Permutations II
49 Group Anagrams
50 Pow(x, n)
53 Maximum Subarray
55 Jump Game
56 Merge Intervals
57 Insert Interval
58 Length of Last Word
60 Permutation Sequence
61 Rotate List
62 Unique Paths
63 Unique Paths II
64 Minimum Path Sum
66 Plus One
69 Sqrt(x)
70 Climbing Stairs
71 Simplify Path
74 Search a 2D Matrix
75 Sort Colors
76 Minimum Window Substring
77 Combinations
78 Subsets
79 Word Search
80 Remove Duplicates from Sorted Array II
82 Remove Duplicates from Sorted List II
83 Remove Duplicates from Sorted List
86 Partition List
87 Scramble String
88 Merge Sorted Array
90 Subsets II
92 Reverse Linked List II
94 Binary Tree Inorder Traversal
98 Validate Binary Search Tree
99 Recover Binary Search Tree
100 Same Tree
101 Symmetric Tree
102 Binary Tree Level Order Traversal
103 Binary Tree Zigzag Level Order Traversal
104 Maximum Depth of Binary Tree
107 Binary Tree Level Order Traversal II
110 Balanced Binary Tree
111 Minimum Depth of Binary Tree
112 Path Sum
113 Path Sum II
121 Best Time to Buy and Sell Stock
122 Best Time to Buy and Sell Stock II
124 Binary Tree Maximum Path Sum
125 Valid Palindrome
127 Word Ladder
129 Sum Root to Leaf Numbers
131 Palindrome Partitioning
136 Single Number
138 Copy List with Random Pointer
139 Word Break
141 Linked List Cycle
142 Linked List Cycle II
143 Reorder List
144 Binary Tree Preorder Traversal
145 Binary Tree Postorder Traversal
148 Sort List
150 Evaluate Reverse Polish Notation
151 Reverse Words in a String
153 Find Minimum in Rotated Sorted Array
154 Find Minimum in Rotated Sorted Array II
155 Min Stack
156 Binary Tree Upside Down
160 Intersection of Two Linked Lists
161 One Edit Distance
162 Find Peak Element
163 Missing Ranges
165 Compare Version Numbers
167 Two Sum II - Input array is sorted
168 Excel Sheet Column Title
169 Majority Element
170 Two Sum III - Data structure design
171 Excel Sheet Column Number
173 Binary Search Tree Iterator
186 Reverse Words in a String II
187 Repeated DNA Sequences
198 House Robber
199 Binary Tree Right Side View
200 Number of Islands
202 Happy Number
203 Remove Linked List Elements
205 Isomorphic Strings
206 Reverse Linked List
209 Minimum Size Subarray Sum
213 House Robber II
214 Shortest Palindrome
215 Kth Largest Element in an Array
216 Combination Sum III
217 Contains Duplicate
219 Contains Duplicate II
220 Contains Duplicate III
221 Maximal Square
224 Basic Calculator
225 Implement Stack using Queues
226 Invert Binary Tree
227 Basic Calculator II
228 Summary Ranges
229 Majority Element II
230 Kth Smallest Element in a BST
232 Implement Queue using Stacks
234 Palindrome Linked List
235 Lowest Common Ancestor of a Binary Search Tree
236 Lowest Common Ancestor of a Binary Tree
237 Delete Node in a Linked List
238 Product of Array Except Self
239 Sliding Window Maximum
240 Search a 2D Matrix II
242 Valid Anagram
243 Shortest Word Distance
244 Shortest Word Distance II
245 Shortest Word Distance III
246 Strobogrammatic Number
247 Strobogrammatic Number II
250 Count Univalue Subtrees
251 Flatten 2D Vector
252 Meeting Rooms
253 Meeting Rooms II
254 Factor Combinations
255 Verify Preorder Sequence in Binary Search Tree
256 Paint House
257 Binary Tree Paths
258 Add Digits
259 3Sum Smaller
263 Ugly Number
264 Ugly Number II
266 Palindrome Permutation
267 Palindrome Permutation II
268 Missing Number
270 Closest Binary Search Tree Value
274 H-Index
275 H-Index II
277 Find the Celebrity
278 First Bad Version
279 Perfect Squares
280 Wiggle Sort
283 Move Zeroes
285 Inorder Successor in BST
286 Walls and Gates
287 Find the Duplicate Number
288 Unique Word Abbreviation
290 Word Pattern
295 Find Median from Data Stream
296 Best Meeting Point
298 Binary Tree Longest Consecutive Sequence
299 Bulls and Cows
300 Longest Increasing Subsequence
303 Range Sum Query - Immutable
304 Range Sum Query 2D - Immutable
305 Number of Islands II
311 Sparse Matrix Multiplication
313 Super Ugly Number
316 Remove Duplicate Letters
320 Generalized Abbreviation
322 Coin Change
325 Maximum Size Subarray Sum Equals k
326 Power of Three
328 Odd Even Linked List
330 Patching Array
334 Increasing Triplet Subsequence
337 House Robber III
339 Nested List Weight Sum
340 Longest Substring with At Most K Distinct Characters
341 Flatten Nested List Iterator
342 Power of Four
344 Reverse String
345 Reverse Vowels of a String
346 Moving Average from Data Stream
347 Top K Frequent Elements
349 Intersection of Two Arrays
350 Intersection of Two Arrays II
356 Line Reflection
359 Logger Rate Limiter
360 Sort Transformed Array
362 Design Hit Counter
365 Water and Jug Problem
366 Find Leaves of Binary Tree
367 Valid Perfect Square
369 Plus One Linked List
370 Range Addition
373 Find K Pairs with Smallest Sums
374 Guess Number Higher or Lower
376 Wiggle Subsequence
377 Combination Sum IV
378 Kth Smallest Element in a Sorted Matrix
379 Design Phone Directory
380 Insert Delete GetRandom O(1)
381 Insert Delete GetRandom O(1) - Duplicates allowed
383 Ransom Note
387 First Unique Character in a String
388 Longest Absolute File Path
389 Find the Difference
392 Is Subsequence
400 Nth Digit
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