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TopicQuestionDifficulty
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1Array, Hash Tablehttps://leetcode.com/problems/two-sumEasyDone
3
3Array, Divide and Conquer, Dynamic Programminghttps://leetcode.com/problems/maximum-subarrayEasy
4
10Array, Dynamic Programminghttps://leetcode.com/problems/best-time-to-buy-and-sell-stockEasy
5
18String, Stackhttps://leetcode.com/problems/valid-parenthesesEasy
6
22Linked List, RecursionReverse Linked List - LeetCodeEasy
7
25Linked List, Recursionhttps://leetcode.com/problems/merge-two-sorted-listsEasy
8
26Math, Dynamic Programming, Memoizationhttps://leetcode.com/problems/climbing-stairsEasy
9
38Tree, Depth-First Search, Breadth-First Search, Binary Treehttps://leetcode.com/problems/symmetric-treeEasy
10
42Array, Bit Manipulationhttps://leetcode.com/problems/single-numberEasy
11
52Array, Two Pointershttps://leetcode.com/problems/move-zeroesEasy
12
53Hash Table, Linked List, Two Pointershttps://leetcode.com/problems/intersection-of-two-linked-listsEasy
13
54Array, Hash Table, Divide and Conquer, Sorting, Countinghttps://leetcode.com/problems/majority-elementEasy
14
57Linked List, Two Pointers, Stack, Recursionhttps://leetcode.com/problems/palindrome-linked-listEasy
15
61Tree, Depth-First Search, Breadth-First Search, Binary Treehttps://leetcode.com/problems/invert-binary-treeEasy
16
64Stack, Design`Easy
17
70Tree, Depth-First Search, Binary Treehttps://leetcode.com/problems/diameter-of-binary-treeEasy
18
73Stack, Tree, Depth-First Search, Binary Treehttps://leetcode.com/problems/binary-tree-inorder-traversalEasy
19
76Hash Table, Linked List, Two Pointershttps://leetcode.com/problems/linked-list-cycleEasy
20
78Stringhttps://leetcode.com/problems/longest-common-prefixEasy
21
83Array, Binary Searchhttps://leetcode.com/problems/search-insert-positionEasy
22
96Array, Hash Tablehttps://leetcode.com/problems/find-all-numbers-disappeared-in-an-arrayEasy
23
98Tree, Depth-First Search, Breadth-First Search, Binary Treehttps://leetcode.com/problems/merge-two-binary-treesEasy
24
106Tree, Depth-First Search, Breadth-First Search, Binary Treehttps://leetcode.com/problems/maximum-depth-of-binary-treeEasy
25
109Array, Divide and Conquer, Tree, Binary Search Tree, Binary Tree
https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree
Easy
26
113Array, Two Pointershttps://leetcode.com/problems/remove-duplicates-from-sorted-arrayEasy
27
118Dynamic Programming, Bit Manipulationhttps://leetcode.com/problems/counting-bitsEasy
28
130Array, Dynamic Programminghttps://leetcode.com/problems/min-cost-climbing-stairsEasy
29
137Tree, Depth-First Search, Binary Treehttps://leetcode.com/problems/balanced-binary-treeEasy
30
138Mathhttps://leetcode.com/problems/palindrome-numberEasy
31
143Tree, Depth-First Search, Breadth-First Search, Binary Treehttps://leetcode.com/problems/same-treeEasy
32
144Tree, Depth-First Search, Binary Search Tree, Binary Tree
https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree
Easy
33
149Tree, Depth-First Search, Binary Treehttps://leetcode.com/problems/path-sumEasy
34
151Tree, Depth-First Search, String Matching, Binary Tree, Hash Functionhttps://leetcode.com/problems/subtree-of-another-treeEasy
35
152Array, Hash Table, Math, Bit Manipulation, Sortinghttps://leetcode.com/problems/missing-numberEasy
36
156Array, Dynamic Programminghttps://leetcode.com/problems/pascals-triangleEasy
37
159Hash Table, Math, Two Pointershttps://leetcode.com/problems/happy-numberEasy
38
165Linked List, Two Pointershttps://leetcode.com/problems/middle-of-the-linked-listEasy
39
172Array, Two Pointers, Binary Searchhttps://leetcode.com/problems/two-sum-ii-input-array-is-sortedEasy
40
173Hash Table, String, Queue, Countinghttps://leetcode.com/problems/first-unique-character-in-a-stringEasy
41
176Array, Two Pointers, Sortinghttps://leetcode.com/problems/squares-of-a-sorted-arrayEasy
42
181Linked List, Recursionhttps://leetcode.com/problems/remove-linked-list-elementsEasy
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197Array, Depth-First Search, Breadth-First Search, Matrixhttps://leetcode.com/problems/island-perimeterEasy
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198Linked Listhttps://leetcode.com/problems/remove-duplicates-from-sorted-listEasy
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199Math, String, Bit Manipulation, Simulationhttps://leetcode.com/problems/add-binaryEasy
46
201Hash Table, String, Sortinghttps://leetcode.com/problems/valid-anagramEasy
47
203Binary Search, Interactivehttps://leetcode.com/problems/first-bad-versionEasy
48
208Two Pointers, String, Greedyhttps://leetcode.com/problems/valid-palindrome-iiEasy
49
209Linked Listhttps://leetcode.com/problems/delete-node-in-a-linked-listEasy
50
216Array, Hash Table, Two Pointers, Binary Search, Sortinghttps://leetcode.com/problems/intersection-of-two-arrays-iiEasy
51
222Two Pointers, String, Recursionhttps://leetcode.com/problems/reverse-stringEasy
52
223Tree, Depth-First Search, Binary Search Tree, Binary Treehttps://leetcode.com/problems/range-sum-of-bstEasy
53
226Stack, Tree, Depth-First Search, Binary Treehttps://leetcode.com/problems/binary-tree-postorder-traversalEasy
54
232Two Pointers, String, Dynamic Programminghttps://leetcode.com/problems/is-subsequenceEasy
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234String, Tree, Depth-First Search, Binary Treehttps://leetcode.com/problems/binary-tree-pathsEasy
56
236Tree, Depth-First Search, Breadth-First Search, Binary Treehttps://leetcode.com/problems/minimum-depth-of-binary-treeEasy
57
242Stack, Tree, Depth-First Search, Binary Treehttps://leetcode.com/problems/binary-tree-preorder-traversalEasy
58
244Array, Mathhttps://leetcode.com/problems/plus-oneEasy
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248Two Pointers, String, Stack, Simulationhttps://leetcode.com/problems/backspace-string-compareEasy
60
251Two Pointers, String, String Matchinghttps://leetcode.com/problems/implement-strstrEasy
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254Array, Hash Table, Sortinghttps://leetcode.com/problems/contains-duplicateEasy
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263Hash Table, Stringhttps://leetcode.com/problems/jewels-and-stonesEasy
63
265Array, Depth-First Search, Breadth-First Search, Matrixhttps://leetcode.com/problems/flood-fillEasy
64
273Hash Table, Two Pointers, Tree, Depth-First Search, Breadth-First Search, Binary Search Tree, Binary Treehttps://leetcode.com/problems/two-sum-iv-input-is-a-bstEasy
65
276Math, Binary Searchhttps://leetcode.com/problems/sqrtxEasy
66
277Hash Table, Stringhttps://leetcode.com/problems/isomorphic-stringsEasy
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279Array, Binary Searchhttps://leetcode.com/problems/binary-searchEasy
68
281String, String Matchinghttps://leetcode.com/problems/repeated-substring-patternEasy
69
282Array, Two Pointershttps://leetcode.com/problems/remove-elementEasy
70
293Tree, Depth-First Search, Breadth-First Search, Binary Treehttps://leetcode.com/problems/sum-of-left-leavesEasy
71
294Bit Manipulationhttps://leetcode.com/problems/hamming-distanceEasy
72
298Two Pointers, Stringhttps://leetcode.com/problems/valid-palindromeEasy
73
307Math, String, Simulationhttps://leetcode.com/problems/add-stringsEasy
74
309Stack, Design, Queuehttps://leetcode.com/problems/implement-queue-using-stacksEasy
75
311Hash Table, Math, Stringhttps://leetcode.com/problems/roman-to-integerEasy
76
312Array, Hash Table, Graphhttps://leetcode.com/problems/find-the-town-judgeEasy
77
314Array, Two Pointers, Sortinghttps://leetcode.com/problems/merge-sorted-arrayEasy
78
315String, Stackhttps://leetcode.com/problems/remove-all-adjacent-duplicates-in-stringEasy
79
318Tree, Depth-First Search, Breadth-First Search, Binary Treehttps://leetcode.com/problems/average-of-levels-in-binary-treeEasy
80
319Array, Prefix Sumhttps://leetcode.com/problems/find-pivot-indexEasy
81
320Array, Hash Table, Sorting, Counting
https://leetcode.com/problems/how-many-numbers-are-smaller-than-the-current-number
Easy
82
323Math, Bit Manipulation, Recursionhttps://leetcode.com/problems/power-of-twoEasy
83
327Math, Dynamic Programming, Recursion, Memoizationhttps://leetcode.com/problems/fibonacci-numberEasy
84
328Divide and Conquer, Bit Manipulationhttps://leetcode.com/problems/reverse-bitsEasy
85
332Hash Table, Stringhttps://leetcode.com/problems/word-patternEasy
86
346Array, Hash Table, Stringhttps://leetcode.com/problems/verifying-an-alien-dictionaryEasy
87
350Tree, Depth-First Search, Breadth-First Search, Binary Treehttps://leetcode.com/problems/cousins-in-binary-treeEasy
88
355Two Pointers, Stringhttps://leetcode.com/problems/count-binary-substringsEasy
89
360Array, Two Pointers, Sortinghttps://leetcode.com/problems/sort-array-by-parityEasy
90
364Bit Manipulationhttps://leetcode.com/problems/number-of-1-bitsEasy
91
366Array, Math, Sortinghttps://leetcode.com/problems/maximum-product-of-three-numbersEasy
92
368Math, Stringhttps://leetcode.com/problems/excel-sheet-column-titleEasy
93
375Array, Hash Table, Two Pointers, Binary Search, Sortinghttps://leetcode.com/problems/intersection-of-two-arraysEasy
94
377Hash Table, String, Greedyhttps://leetcode.com/problems/longest-palindromeEasy
95
378Tree, Binary Search Tree, Binary Treehttps://leetcode.com/problems/search-in-a-binary-search-treeEasy
96
382Two Pointers, Stringhttps://leetcode.com/problems/reverse-words-in-a-string-iiiEasy
97
383Math, Stringhttps://leetcode.com/problems/excel-sheet-column-numberEasy
98
385Array, Hash Table, Linked List, Design, Hash Functionhttps://leetcode.com/problems/design-hashmapEasy
99
389Linked List, Math
https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer
Easy
100
391Arrayhttps://leetcode.com/problems/max-consecutive-onesEasy