LeetCode

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LeetCode solutions gives some thoughts on selected problems.

Solved 373/373 problems.

Database

See database.md

Algorithms

#	Title	Solution
391	Perfect Rectangle	perfect-rectangle.cc
389	Find the Difference	find-the-difference.cc
388	Longest Absolute File Path	longest-absolute-file-path.cc
387	First Unique Character in a String	first-unique-character-in-a-string.cc
386	Lexicographical Numbers	lexicographical-numbers.cc
385	Mini Parser	mini-parser.cc
384	Shuffle an Array	shuffle-an-array.cc
383	Ransom Note	ransom-note.cc
382	Linked List Random Node	linked-list-random-node.cc
381	Insert Delete GetRandom O(1) - Duplicates allowed	insert-delete-getrandom-o1-duplicates-allowed.cc
380	Insert Delete GetRandom O(1)	insert-delete-getrandom-o1.cc
379	Design Phone Directory	design-phone-directory.cc
378	Kth Smallest Element in a Sorted Matrix	kth-smallest-element-in-a-sorted-matrix.cc
377	Combination Sum IV	combination-sum-iv.cc
376	Wiggle Subsequence	wiggle-subsequence.cc
375	Guess Number Higher or Lower II	guess-number-higher-or-lower-ii.cc
374	Guess Number Higher or Lower	guess-number-higher-or-lower.cc
373	Find K Pairs with Smallest Sums	find-k-pairs-with-smallest-sums.cc
372	Super Pow	super-pow.cc
371	Sum of Two Integers	sum-of-two-integers.cc
370	Range Addition	range-addition.cc
369	Plus One Linked List	plus-one-linked-list.cc
368	Largest Divisible Subset	largest-divisible-subset.cc
367	Valid Perfect Square	valid-perfect-square.cc
366	Find Leaves of Binary Tree	find-leaves-of-binary-tree.cc
365	Water and Jug Problem	water-and-jug-problem.cc
364	Nested List Weight Sum II	nested-list-weight-sum-ii.cc
363	Max Sum of Rectangle No Larger Than K	max-sum-of-sub-matrix-no-larger-than-k.cc
362	Design Hit Counter	design-hit-counter.cc
361	Bomb Enemy	bomb-enemy.cc
360	Sort Transformed Array	sort-transformed-array.cc
359	Logger Rate Limiter	logger-rate-limiter.cc
358	Rearrange String k Distance Apart	rearrange-string-k-distance-apart.cc
357	Count Numbers with Unique Digits	count-numbers-with-unique-digits.cc
356	Line Reflection	line-reflection.cc
355	Design Twitter	design-twitter.cc
354	Russian Doll Envelopes	russian-doll-envelopes.cc
353	Design Snake Game	design-snake-game.cc
352	Data Stream as Disjoint Intervals	data-stream-as-disjoint-intervals.cc
351	Android Unlock Patterns	android-unlock-patterns.cc
350	Intersection of Two Arrays II	intersection-of-two-arrays-ii.cc
349	Intersection of Two Arrays	intersection-of-two-arrays.cc
348	Design Tic-Tac-Toe	design-tic-tac-toe.cc
347	Top K Frequent Elements	top-k-frequent-elements.cc
346	Moving Average from Data Stream	moving-average-from-data-stream.cc
345	Reverse Vowels of a String	reverse-vowels-of-a-string.cc
344	Reverse String	reverse-string.cc
343	Integer Break	integer-break.cc
342	Power of Four	power-of-four.cc
341	Flatten Nested List Iterator	flatten-nested-list-iterator.cc
340	Longest Substring with At Most K Distinct Characters	longest-substring-with-at-most-k-distinct-characters.cc
339	Nested List Weight Sum	nested-list-weight-sum.cc
338	Counting Bits	counting-bits.cc
337	House Robber III	house-robber-iii.cc
336	Palindrome Pairs	palindrome-pairs.cc
335	Self Crossing	self-crossing.cc
334	Increasing Triplet Subsequence	increasing-triplet-subsequence.cc
333	Largest BST Subtree	largest-bst-subtree.cc
332	Reconstruct Itinerary	reconstruct-itinerary.cc
331	Verify Preorder Serialization of a Binary Tree	verify-preorder-serialization-of-a-binary-tree.cc
330	Patching Array	patching-array.cc
329	Longest Increasing Path in a Matrix	longest-increasing-path-in-a-matrix.cc
328	Odd Even Linked List	odd-even-linked-list.cc
327	Count of Range Sum	count-of-range-sum.cc
326	Power of Three	power-of-three.cc
325	Maximum Size Subarray Sum Equals k	maximum-size-subarray-sum-equals-k.cc
324	Wiggle Sort II	wiggle-sort-ii.cc
323	Number of Connected Components in an Undirected Graph	number-of-connected-components-in-an-undirected-graph.cc
322	Coin Change	coin-change.cc
321	Create Maximum Number	create-maximum-number.cc
320	Generalized Abbreviation	generalized-abbreviation.cc
319	Bulb Switcher	bulb-switcher.cc
318	Maximum Product of Word Lengths	maximum-product-of-word-lengths.cc
317	Shortest Distance from All Buildings	shortest-distance-from-all-buildings.cc
316	Remove Duplicate Letters	remove-duplicate-letters.cc
315	Count of Smaller Numbers After Self	count-of-smaller-numbers-after-self.cc
314	Binary Tree Vertical Order Traversal	binary-tree-vertical-order-traversal.cc
313	Super Ugly Number	super-ugly-number.cc
312	Burst Balloons	burst-balloons.cc
311	Sparse Matrix Multiplication	sparse-matrix-multiplication.cc
310	Minimum Height Trees	minimum-height-trees.cc
309	Best Time to Buy and Sell Stock with Cooldown	best-time-to-buy-and-sell-stock-with-cooldown.cc
308	Range Sum Query 2D - Mutable	range-sum-query-2d-mutable.cc
307	Range Sum Query - Mutable	range-sum-query-mutable.cc
306	Additive Number	additive-number.cc
305	Number of Islands II	number-of-islands-ii.cc
304	Range Sum Query 2D - Immutable	range-sum-query-2d-immutable.cc
303	Range Sum Query - Immutable	range-sum-query-immutable.cc
302	Smallest Rectangle Enclosing Black Pixels	smallest-rectangle-enclosing-black-pixels.cc
301	Remove Invalid Parentheses	remove-invalid-parentheses.cc
300	Longest Increasing Subsequence	longest-increasing-subsequence.cc
299	Bulls and Cows	bulls-and-cows.cc
298	Binary Tree Longest Consecutive Sequence	binary-tree-longest-consecutive-sequence.cc
297	Serialize and Deserialize Binary Tree	serialize-and-deserialize-binary-tree.cc
296	Best Meeting Point	best-meeting-point.cc
295	Find Median from Data Stream	find-median-from-data-stream.cc
294	Flip Game II	flip-game-ii.cc
293	Flip Game	flip-game.cc
292	Nim Game	nim-game.cc
291	Word Pattern II	word-pattern-ii.cc
290	Word Pattern	word-pattern.cc
289	Game of Life	game-of-life.cc
288	Unique Word Abbreviation	unique-word-abbreviation.cc
287	Find the Duplicate Number	find-the-duplicate-number.cc
286	Walls and Gates	walls-and-gates.cc
285	Inorder Successor in BST	inorder-successor-in-bst.cc
284	Peeking Iterator	peeking-iterator.cc
283	Move Zeroes	move-zeroes.cc
282	Expression Add Operators	expression-add-operators.cc
281	Zigzag Iterator	zigzag-iterator.cc
280	Wiggle Sort	wiggle-sort.cc
279	Perfect Squares	perfect-squares.cc
278	First Bad Version	first-bad-version.cc
277	Find the Celebrity	find-the-celebrity.cc
276	Paint Fence	paint-fence.cc
275	H-Index II	h-index-ii.cc
274	H-Index	h-index.cc
273	Integer to English Words	integer-to-english-words.cc
272	Closest Binary Search Tree Value II	closest-binary-search-tree-value-ii.cc
271	Encode and Decode Strings	encode-and-decode-strings.cc
270	Closest Binary Search Tree Value	closest-binary-search-tree-value.cc
269	Alien Dictionary	alien-dictionary.cc
268	Missing Number	missing-number.cc
267	Palindrome Permutation II	palindrome-permutation-ii.cc
266	Palindrome Permutation	palindrome-permutation.cc
265	Paint House II	paint-house-ii.cc
264	Ugly Number II	ugly-number-ii.cc
263	Ugly Number	ugly-number.cc
261	Graph Valid Tree	graph-valid-tree.cc
260	Single Number III	single-number-iii.cc
259	3Sum Smaller	3sum-smaller.cc
258	Add Digits	add-digits.cc
257	Binary Tree Paths	binary-tree-paths.cc
256	Paint House	paint-house.cc
255	Verify Preorder Sequence in Binary Search Tree	verify-preorder-sequence-in-binary-search-tree.cc
254	Factor Combinations	factor-combinations.cc
253	Meeting Rooms II	meeting-rooms-ii.cc
252	Meeting Rooms	meeting-rooms.cc
251	Flatten 2D Vector	flatten-2d-vector.cc
250	Count Univalue Subtrees	count-univalue-subtrees.cc
249	Group Shifted Strings	group-shifted-strings.cc
248	Strobogrammatic Number III	strobogrammatic-number-iii.cc
247	Strobogrammatic Number II	strobogrammatic-number-ii.cc
246	Strobogrammatic Number	strobogrammatic-number.cc
245	Shortest Word Distance III	shortest-word-distance-iii.cc
244	Shortest Word Distance II	shortest-word-distance-ii.cc
243	Shortest Word Distance	shortest-word-distance.cc
242	Valid Anagram	valid-anagram.cc
241	Different Ways to Add Parentheses	different-ways-to-add-parentheses.cc
240	Search a 2D Matrix II	search-a-2d-matrix-ii.cc
239	Sliding Window Maximum	sliding-window-maximum.cc
238	Product of Array Except Self	product-of-array-except-self.cc
237	Delete Node in a Linked List	delete-node-in-a-linked-list.cc
236	Lowest Common Ancestor of a Binary Tree	lowest-common-ancestor-of-a-binary-tree.cc
235	Lowest Common Ancestor of a Binary Search Tree	lowest-common-ancestor-of-a-binary-search-tree.cc
234	Palindrome Linked List	palindrome-linked-list.cc
233	Number of Digit One	number-of-digit-one.cc
232	Implement Queue using Stacks	implement-queue-using-stacks.cc
231	Power of Two	power-of-two.cc
230	Kth Smallest Element in a BST	kth-smallest-element-in-a-bst.cc
229	Majority Element II	majority-element-ii.cc
228	Summary Ranges	summary-ranges.cc
227	Basic Calculator II	basic-calculator-ii.cc
226	Invert Binary Tree	invert-binary-tree.cc
225	Implement Stack using Queues	implement-stack-using-queues.cc
224	Basic Calculator	basic-calculator.cc
223	Rectangle Area	rectangle-area.cc
222	Count Complete Tree Nodes	count-complete-tree-nodes.cc
221	Maximal Square	maximal-square.cc
220	Contains Duplicate III	contains-duplicate-iii.cc
219	Contains Duplicate II	contains-duplicate-ii.cc
218	The Skyline Problem	the-skyline-problem.cc
217	Contains Duplicate	contains-duplicate.cc
216	Combination Sum III	combination-sum-iii.cc
215	Kth Largest Element in an Array	kth-largest-element-in-an-array.cc
214	Shortest Palindrome	shortest-palindrome.cc
213	House Robber II	house-robber-ii.cc
212	Word Search II	word-search-ii.cc
211	Add and Search Word - Data structure design	add-and-search-word-data-structure-design.cc
210	Course Schedule II	course-schedule-ii.cc
209	Minimum Size Subarray Sum	minimum-size-subarray-sum.cc
208	Implement Trie (Prefix Tree)	implement-trie-prefix-tree.cc
207	Course Schedule	course-schedule.cc
206	Reverse Linked List	reverse-linked-list.cc
205	Isomorphic Strings	isomorphic-strings.cc
204	Count Primes	count-primes.cc
203	Remove Linked List Elements	remove-linked-list-elements.cc
202	Happy Number	happy-number.cc
201	Bitwise AND of Numbers Range	bitwise-and-of-numbers-range.cc
200	Number of Islands	number-of-islands.cc
199	Binary Tree Right Side View	binary-tree-right-side-view.cc
198	House Robber	house-robber.cc
191	Number of 1 Bits	number-of-1-bits.cc
190	Reverse Bits	reverse-bits.cc
189	Rotate Array	rotate-array.cc
188	Best Time to Buy and Sell Stock IV	best-time-to-buy-and-sell-stock-iv.cc
187	Repeated DNA Sequences	repeated-dna-sequences.cc
186	Reverse Words in a String II	reverse-words-in-a-string-ii.cc
179	Largest Number	largest-number.cc
174	Dungeon Game	dungeon-game.cc
173	Binary Search Tree Iterator	binary-search-tree-iterator.cc
172	Factorial Trailing Zeroes	factorial-trailing-zeroes.cc
171	Excel Sheet Column Number	excel-sheet-column-number.cc
170	Two Sum III - Data structure design	two-sum-iii-data-structure-design.cc
169	Majority Element	majority-element.cc
168	Excel Sheet Column Title	excel-sheet-column-title.cc
167	Two Sum II - Input array is sorted	two-sum-ii-input-array-is-sorted.cc
166	Fraction to Recurring Decimal	fraction-to-recurring-decimal.cc
165	Compare Version Numbers	compare-version-numbers.cc
164	Maximum Gap	maximum-gap.cc
163	Missing Ranges	missing-ranges.cc
162	Find Peak Element	find-peak-element.cc
161	One Edit Distance	one-edit-distance.cc
160	Intersection of Two Linked Lists	intersection-of-two-linked-lists.cc
159	Longest Substring with At Most Two Distinct Characters	longest-substring-with-at-most-two-distinct-characters.cc
158	Read N Characters Given Read4 II - Call multiple times	read-n-characters-given-read4-ii-call-multiple-times.cc
157	Read N Characters Given Read4	read-n-characters-given-read4.cc
156	Binary Tree Upside Down	binary-tree-upside-down.cc
155	Min Stack	min-stack.cc
154	Find Minimum in Rotated Sorted Array II	find-minimum-in-rotated-sorted-array-ii.cc
153	Find Minimum in Rotated Sorted Array	find-minimum-in-rotated-sorted-array.cc
152	Maximum Product Subarray	maximum-product-subarray.cc
151	Reverse Words in a String	reverse-words-in-a-string.cc
150	Evaluate Reverse Polish Notation	evaluate-reverse-polish-notation.cc
149	Max Points on a Line	max-points-on-a-line.cc
148	Sort List	sort-list.cc
147	Insertion Sort List	insertion-sort-list.cc
146	LRU Cache	lru-cache.cc
145	Binary Tree Postorder Traversal	binary-tree-postorder-traversal.cc
144	Binary Tree Preorder Traversal	binary-tree-preorder-traversal.cc
143	Reorder List	reorder-list.cc
142	Linked List Cycle II	linked-list-cycle-ii.cc
141	Linked List Cycle	linked-list-cycle.cc
140	Word Break II	word-break-ii.cc
139	Word Break	word-break.cc
138	Copy List with Random Pointer	copy-list-with-random-pointer.cc
137	Single Number II	single-number-ii.cc
136	Single Number	single-number.cc
135	Candy	candy.cc
134	Gas Station	gas-station.cc
133	Clone Graph	clone-graph.cc
132	Palindrome Partitioning II	palindrome-partitioning-ii.cc
131	Palindrome Partitioning	palindrome-partitioning.cc
130	Surrounded Regions	surrounded-regions.cc
129	Sum Root to Leaf Numbers	sum-root-to-leaf-numbers.cc
128	Longest Consecutive Sequence	longest-consecutive-sequence.cc
127	Word Ladder	word-ladder.cc
126	Word Ladder II	word-ladder-ii.cc
125	Valid Palindrome	valid-palindrome.cc
124	Binary Tree Maximum Path Sum	binary-tree-maximum-path-sum.cc
123	Best Time to Buy and Sell Stock III	best-time-to-buy-and-sell-stock-iii.cc
122	Best Time to Buy and Sell Stock II	best-time-to-buy-and-sell-stock-ii.cc
121	Best Time to Buy and Sell Stock	best-time-to-buy-and-sell-stock.cc
120	Triangle	triangle.cc
119	Pascal's Triangle II	pascals-triangle-ii.cc
118	Pascal's Triangle	pascals-triangle.cc
117	Populating Next Right Pointers in Each Node II	populating-next-right-pointers-in-each-node-ii.cc
116	Populating Next Right Pointers in Each Node	populating-next-right-pointers-in-each-node.cc
115	Distinct Subsequences	distinct-subsequences.cc
114	Flatten Binary Tree to Linked List	flatten-binary-tree-to-linked-list.cc
113	Path Sum II	path-sum-ii.cc
112	Path Sum	path-sum.cc
111	Minimum Depth of Binary Tree	minimum-depth-of-binary-tree.cc
110	Balanced Binary Tree	balanced-binary-tree.cc
109	Convert Sorted List to Binary Search Tree	convert-sorted-list-to-binary-search-tree.cc
108	Convert Sorted Array to Binary Search Tree	convert-sorted-array-to-binary-search-tree.cc
107	Binary Tree Level Order Traversal II	binary-tree-level-order-traversal-ii.cc
106	Construct Binary Tree from Inorder and Postorder Traversal	construct-binary-tree-from-inorder-and-postorder-traversal.cc
105	Construct Binary Tree from Preorder and Inorder Traversal	construct-binary-tree-from-preorder-and-inorder-traversal.cc
104	Maximum Depth of Binary Tree	maximum-depth-of-binary-tree.cc
103	Binary Tree Zigzag Level Order Traversal	binary-tree-zigzag-level-order-traversal.cc
102	Binary Tree Level Order Traversal	binary-tree-level-order-traversal.cc
101	Symmetric Tree	symmetric-tree.cc
100	Same Tree	same-tree.cc
99	Recover Binary Search Tree	recover-binary-search-tree.cc
98	Validate Binary Search Tree	validate-binary-search-tree.cc
97	Interleaving String	interleaving-string.cc
96	Unique Binary Search Trees	unique-binary-search-trees.cc
95	Unique Binary Search Trees II	unique-binary-search-trees-ii.cc
94	Binary Tree Inorder Traversal	binary-tree-inorder-traversal.cc
93	Restore IP Addresses	restore-ip-addresses.cc
92	Reverse Linked List II	reverse-linked-list-ii.cc
91	Decode Ways	decode-ways.cc
90	Subsets II	subsets-ii.cc
89	Gray Code	gray-code.cc
88	Merge Sorted Array	merge-sorted-array.cc
87	Scramble String	scramble-string.cc
86	Partition List	partition-list.cc
85	Maximal Rectangle	maximal-rectangle.cc
84	Largest Rectangle in Histogram	largest-rectangle-in-histogram.cc
83	Remove Duplicates from Sorted List	remove-duplicates-from-sorted-list.cc
82	Remove Duplicates from Sorted List II	remove-duplicates-from-sorted-list-ii.cc
81	Search in Rotated Sorted Array II	search-in-rotated-sorted-array-ii.cc
80	Remove Duplicates from Sorted Array II	remove-duplicates-from-sorted-array-ii.cc
79	Word Search	word-search.cc
78	Subsets	subsets.cc
77	Combinations	combinations.cc
76	Minimum Window Substring	minimum-window-substring.cc
75	Sort Colors	sort-colors.cc
74	Search a 2D Matrix	search-a-2d-matrix.cc
73	Set Matrix Zeroes	set-matrix-zeroes.cc
72	Edit Distance	edit-distance.cc
71	Simplify Path	simplify-path.cc
70	Climbing Stairs	climbing-stairs.cc
69	Sqrt(x)	sqrtx.cc
68	Text Justification	text-justification.cc
67	Add Binary	add-binary.cc
66	Plus One	plus-one.cc
65	Valid Number	valid-number.cc
64	Minimum Path Sum	minimum-path-sum.cc
63	Unique Paths II	unique-paths-ii.cc
62	Unique Paths	unique-paths.cc
61	Rotate List	rotate-list.cc
60	Permutation Sequence	permutation-sequence.cc
59	Spiral Matrix II	spiral-matrix-ii.cc
58	Length of Last Word	length-of-last-word.cc
57	Insert Interval	insert-interval.cc
56	Merge Intervals	merge-intervals.cc
55	Jump Game	jump-game.cc
54	Spiral Matrix	spiral-matrix.cc
53	Maximum Subarray	maximum-subarray.cc
52	N-Queens II	n-queens-ii.cc
51	N-Queens	n-queens.cc
50	Pow(x, n)	powx-n.cc
49	Group Anagrams	anagrams.cc
48	Rotate Image	rotate-image.cc
47	Permutations II	permutations-ii.cc
46	Permutations	permutations.cc
45	Jump Game II	jump-game-ii.cc
44	Wildcard Matching	wildcard-matching.cc
43	Multiply Strings	multiply-strings.cc
42	Trapping Rain Water	trapping-rain-water.cc
41	First Missing Positive	first-missing-positive.cc
40	Combination Sum II	combination-sum-ii.cc
39	Combination Sum	combination-sum.cc
38	Count and Say	count-and-say.cc
37	Sudoku Solver	sudoku-solver.cc
36	Valid Sudoku	valid-sudoku.cc
35	Search Insert Position	search-insert-position.cc
34	Search for a Range	search-for-a-range.cc
33	Search in Rotated Sorted Array	search-in-rotated-sorted-array.cc
32	Longest Valid Parentheses	longest-valid-parentheses.cc
31	Next Permutation	next-permutation.cc
30	Substring with Concatenation of All Words	substring-with-concatenation-of-all-words.cc
29	Divide Two Integers	divide-two-integers.cc
28	Implement strStr()	implement-strstr.cc
27	Remove Element	remove-element.cc
26	Remove Duplicates from Sorted Array	remove-duplicates-from-sorted-array.cc
25	Reverse Nodes in k-Group	reverse-nodes-in-k-group.cc
24	Swap Nodes in Pairs	swap-nodes-in-pairs.cc
23	Merge k Sorted Lists	merge-k-sorted-lists.cc
22	Generate Parentheses	generate-parentheses.cc
21	Merge Two Sorted Lists	merge-two-sorted-lists.cc
20	Valid Parentheses	valid-parentheses.cc
19	Remove Nth Node From End of List	remove-nth-node-from-end-of-list.cc
18	4Sum	4sum.cc
17	Letter Combinations of a Phone Number	letter-combinations-of-a-phone-number.cc
16	3Sum Closest	3sum-closest.cc
15	3Sum	3sum.cc
14	Longest Common Prefix	longest-common-prefix.cc
13	Roman to Integer	roman-to-integer.cc
12	Integer to Roman	integer-to-roman.cc
11	Container With Most Water	container-with-most-water.cc
10	Regular Expression Matching	regular-expression-matching.cc
9	Palindrome Number	palindrome-number.cc
8	String to Integer (atoi)	string-to-integer-atoi.cc
7	Reverse Integer	reverse-integer.cc
6	ZigZag Conversion	zigzag-conversion.cc
5	Longest Palindromic Substring	longest-palindromic-substring.cc
4	Median of Two Sorted Arrays	median-of-two-sorted-arrays.cc
3	Longest Substring Without Repeating Characters	longest-substring-without-repeating-characters.cc
2	Add Two Numbers	add-two-numbers.cc
1	Two Sum	two-sum.cc