✏️ Leetcode Solutions with C++

Update time: 2017-10-02 12:11:55

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#	Title	Source Code	Article	Difficulty
1	two-sum	Cpp	📝	Easy
2	add-two-numbers		📝	Medium
3	longest-substring-without-repeating-characters		📝	Medium
4	median-of-two-sorted-arrays		📝	Hard
5	longest-palindromic-substring		📝	Medium
6	zigzag-conversion			Medium
7	reverse-integer	Cpp		Easy
8	string-to-integer-atoi			Medium
9	palindrome-number		📝	Easy
10	regular-expression-matching		📝	Hard
11	container-with-most-water		📝	Medium
12	integer-to-roman			Medium
13	roman-to-integer	Cpp		Easy
14	longest-common-prefix		📝	Easy
15	3sum			Medium
16	3sum-closest			Medium
17	letter-combinations-of-a-phone-number			Medium
18	4sum			Medium
19	remove-nth-node-from-end-of-list		📝	Medium
20	valid-parentheses	Cpp		Easy
21	merge-two-sorted-lists			Easy
22	generate-parentheses			Medium
23	merge-k-sorted-lists		📝	Hard
24	swap-nodes-in-pairs			Medium
25	reverse-nodes-in-k-group			Hard
26	remove-duplicates-from-sorted-array	Cpp	📝	Easy
27	remove-element	Cpp	📝	Easy
28	implement-strstr	Cpp		Easy
29	divide-two-integers			Medium
30	substring-with-concatenation-of-all-words			Hard
31	next-permutation	Cpp	📝	Medium
32	longest-valid-parentheses		📝	Hard
33	search-in-rotated-sorted-array			Medium
34	search-for-a-range	Cpp		Medium
35	search-insert-position	Cpp		Easy
36	valid-sudoku	Cpp		Medium
37	sudoku-solver			Hard
38	count-and-say			Easy
39	combination-sum			Medium
40	combination-sum-ii			Medium
41	first-missing-positive	Cpp		Hard
42	trapping-rain-water		📝	Hard
43	multiply-strings			Medium
44	wildcard-matching			Hard
45	jump-game-ii			Hard
46	permutations	Cpp		Medium
47	permutations-ii	Cpp		Medium
48	rotate-image			Medium
49	group-anagrams	Cpp	📝	Medium
50	powx-n	Cpp		Medium
51	n-queens			Hard
52	n-queens-ii			Hard
53	maximum-subarray	Cpp		Easy
54	spiral-matrix		📝	Medium
55	jump-game		📝	Medium
56	merge-intervals			Medium
57	insert-interval			Hard
58	length-of-last-word			Easy
59	spiral-matrix-ii			Medium
60	permutation-sequence	Cpp		Medium
61	rotate-list			Medium
62	unique-paths			Medium
63	unique-paths-ii			Medium
64	minimum-path-sum		📝	Medium
65	valid-number			Hard
66	plus-one	Cpp		Easy
67	add-binary			Easy
68	text-justification			Hard
69	sqrtx	Cpp		Easy
70	climbing-stairs	Cpp	📝	Easy
71	simplify-path			Medium
72	edit-distance	Cpp		Hard
73	set-matrix-zeroes	Cpp		Medium
74	search-a-2d-matrix			Medium
75	sort-colors	Cpp		Medium
76	minimum-window-substring			Hard
77	combinations			Medium
78	subsets			Medium
79	word-search			Medium
80	remove-duplicates-from-sorted-array-ii			Medium
81	search-in-rotated-sorted-array-ii			Medium
82	remove-duplicates-from-sorted-list-ii			Medium
83	remove-duplicates-from-sorted-list		📝	Easy
84	largest-rectangle-in-histogram		📝	Hard
85	maximal-rectangle			Hard
86	partition-list			Medium
87	scramble-string			Hard
88	merge-sorted-array			Easy
89	gray-code			Medium
90	subsets-ii			Medium
91	decode-ways			Medium
92	reverse-linked-list-ii			Medium
93	restore-ip-addresses			Medium
94	binary-tree-inorder-traversal		📝	Medium
95	unique-binary-search-trees-ii			Medium
96	unique-binary-search-trees			Medium
97	interleaving-string		📝	Hard
98	validate-binary-search-tree			Medium
99	recover-binary-search-tree			Hard
100	same-tree	Cpp		Easy
101	symmetric-tree		📝	Easy
102	binary-tree-level-order-traversal			Medium
103	binary-tree-zigzag-level-order-traversal			Medium
104	maximum-depth-of-binary-tree	Cpp		Easy
105	construct-binary-tree-from-preorder-and-inorder-traversal			Medium
106	construct-binary-tree-from-inorder-and-postorder-traversal			Medium
107	binary-tree-level-order-traversal-ii			Easy
108	convert-sorted-array-to-binary-search-tree			Easy
109	convert-sorted-list-to-binary-search-tree			Medium
110	balanced-binary-tree			Easy
111	minimum-depth-of-binary-tree			Easy
112	path-sum	Cpp		Easy
113	path-sum-ii			Medium
114	flatten-binary-tree-to-linked-list			Medium
115	distinct-subsequences			Hard
116	populating-next-right-pointers-in-each-node			Medium
117	populating-next-right-pointers-in-each-node-ii			Medium
118	pascals-triangle	Cpp		Easy
119	pascals-triangle-ii			Easy
120	triangle	Cpp		Medium
121	best-time-to-buy-and-sell-stock	Cpp	📝	Easy
122	best-time-to-buy-and-sell-stock-ii	Cpp	📝	Easy
123	best-time-to-buy-and-sell-stock-iii			Hard
124	binary-tree-maximum-path-sum			Hard
125	valid-palindrome			Easy
126	word-ladder-ii			Hard
127	word-ladder			Medium
128	longest-consecutive-sequence	Cpp		Hard
129	sum-root-to-leaf-numbers			Medium
130	surrounded-regions			Medium
131	palindrome-partitioning			Medium
132	palindrome-partitioning-ii			Hard
133	clone-graph			Medium
134	gas-station			Medium
135	candy		📝	Hard
136	single-number	Cpp	📝	Easy
137	single-number-ii			Medium
138	copy-list-with-random-pointer			Medium
139	word-break		📝	Medium
140	word-break-ii		📝	Hard
141	linked-list-cycle		📝	Easy
142	linked-list-cycle-ii			Medium
143	reorder-list			Medium
144	binary-tree-preorder-traversal	Cpp		Medium
145	binary-tree-postorder-traversal	Cpp		Hard
146	lru-cache			Hard
147	insertion-sort-list			Medium
148	sort-list			Medium
149	max-points-on-a-line	Cpp		Hard
150	evaluate-reverse-polish-notation	Cpp		Medium
151	reverse-words-in-a-string			Medium
152	maximum-product-subarray			Medium
153	find-minimum-in-rotated-sorted-array			Medium
154	find-minimum-in-rotated-sorted-array-ii			Hard
155	min-stack	Cpp		Easy
156	binary-tree-upside-down	🔒		Medium
157	read-n-characters-given-read4	🔒		Easy
158	read-n-characters-given-read4-ii-call-multiple-times	🔒		Hard
159	longest-substring-with-at-most-two-distinct-characters	🔒		Hard
160	intersection-of-two-linked-lists		📝	Easy
161	one-edit-distance	🔒		Medium
162	find-peak-element	Cpp	📝	Medium
163	missing-ranges	🔒		Medium
164	maximum-gap		📝	Hard
165	compare-version-numbers			Medium
166	fraction-to-recurring-decimal		📝	Medium
167	two-sum-ii-input-array-is-sorted		📝	Easy
168	excel-sheet-column-title	Cpp		Easy
169	majority-element	Cpp		Easy
170	two-sum-iii-data-structure-design	🔒		Easy
171	excel-sheet-column-number	Cpp		Easy
172	factorial-trailing-zeroes			Easy
173	binary-search-tree-iterator			Medium
174	dungeon-game			Hard
179	largest-number			Medium
186	reverse-words-in-a-string-ii	🔒		Medium
187	repeated-dna-sequences			Medium
188	best-time-to-buy-and-sell-stock-iv			Hard
189	rotate-array	Cpp	📝	Easy
190	reverse-bits			Easy
191	number-of-1-bits	Cpp	📝	Easy
198	house-robber		📝	Easy
199	binary-tree-right-side-view			Medium
200	number-of-islands			Medium
201	bitwise-and-of-numbers-range			Medium
202	happy-number			Easy
203	remove-linked-list-elements			Easy
204	count-primes			Easy
205	isomorphic-strings			Easy
206	reverse-linked-list		📝	Easy
207	course-schedule			Medium
208	implement-trie-prefix-tree		📝	Medium
209	minimum-size-subarray-sum		📝	Medium
210	course-schedule-ii	Cpp		Medium
211	add-and-search-word-data-structure-design			Medium
212	word-search-ii			Hard
213	house-robber-ii			Medium
214	shortest-palindrome		📝	Hard
215	kth-largest-element-in-an-array			Medium
216	combination-sum-iii			Medium
217	contains-duplicate	Cpp	📝	Easy
218	the-skyline-problem			Hard
219	contains-duplicate-ii		📝	Easy
220	contains-duplicate-iii		📝	Medium
221	maximal-square		📝	Medium
222	count-complete-tree-nodes			Medium
223	rectangle-area			Medium
224	basic-calculator			Hard
225	implement-stack-using-queues		📝	Easy
226	invert-binary-tree	Cpp	📝	Easy
227	basic-calculator-ii			Medium
228	summary-ranges	Cpp	📝	Medium
229	majority-element-ii			Medium
230	kth-smallest-element-in-a-bst			Medium
231	power-of-two	Cpp		Easy
232	implement-queue-using-stacks		📝	Easy
233	number-of-digit-one		📝	Hard
234	palindrome-linked-list			Easy
235	lowest-common-ancestor-of-a-binary-search-tree			Easy
236	lowest-common-ancestor-of-a-binary-tree			Medium
237	delete-node-in-a-linked-list	Cpp	📝	Easy
238	product-of-array-except-self			Medium
239	sliding-window-maximum			Hard
240	search-a-2d-matrix-ii			Medium
241	different-ways-to-add-parentheses			Medium
242	valid-anagram	Cpp	📝	Easy
243	shortest-word-distance	🔒	📝	Easy
244	shortest-word-distance-ii	🔒		Medium
245	shortest-word-distance-iii	🔒		Medium
246	strobogrammatic-number	🔒		Easy
247	strobogrammatic-number-ii	🔒		Medium
248	strobogrammatic-number-iii	🔒		Hard
249	group-shifted-strings	🔒		Medium
250	count-univalue-subtrees	🔒		Medium
251	flatten-2d-vector	🔒		Medium
252	meeting-rooms	🔒	📝	Easy
253	meeting-rooms-ii	🔒		Medium
254	factor-combinations	🔒		Medium
255	verify-preorder-sequence-in-binary-search-tree	🔒		Medium
256	paint-house	🔒		Easy
257	binary-tree-paths			Easy
258	add-digits			Easy
259	3sum-smaller	🔒	📝	Medium
260	single-number-iii			Medium
261	graph-valid-tree	🔒		Medium
263	ugly-number			Easy
264	ugly-number-ii			Medium
265	paint-house-ii	🔒		Hard
266	palindrome-permutation	🔒	📝	Easy
267	palindrome-permutation-ii	🔒	📝	Medium
268	missing-number			Easy
269	alien-dictionary	🔒		Hard
270	closest-binary-search-tree-value	🔒		Easy
271	encode-and-decode-strings	🔒		Medium
272	closest-binary-search-tree-value-ii	🔒		Hard
273	integer-to-english-words			Hard
274	h-index	Cpp	📝	Medium
275	h-index-ii			Medium
276	paint-fence	🔒		Easy
277	find-the-celebrity	🔒		Medium
278	first-bad-version		📝	Easy
279	perfect-squares			Medium
280	wiggle-sort	🔒	📝	Medium
281	zigzag-iterator	🔒		Medium
282	expression-add-operators			Hard
283	move-zeroes	Cpp	📝	Easy
284	peeking-iterator			Medium
285	inorder-successor-in-bst	🔒		Medium
286	walls-and-gates	🔒	📝	Medium
287	find-the-duplicate-number	Cpp		Medium
288	unique-word-abbreviation	🔒	📝	Medium
289	game-of-life			Medium
290	word-pattern			Easy
291	word-pattern-ii	🔒		Hard
292	nim-game	Cpp	📝	Easy
293	flip-game	🔒		Easy
294	flip-game-ii	🔒		Medium
295	find-median-from-data-stream		📝	Hard
296	best-meeting-point	🔒	📝	Hard
297	serialize-and-deserialize-binary-tree			Hard
298	binary-tree-longest-consecutive-sequence	🔒	📝	Medium
299	bulls-and-cows			Medium
300	longest-increasing-subsequence	Cpp	📝	Medium
301	remove-invalid-parentheses			Hard
302	smallest-rectangle-enclosing-black-pixels	🔒	📝	Hard
303	range-sum-query-immutable	Cpp	📝	Easy
304	range-sum-query-2d-immutable		📝	Medium
305	number-of-islands-ii	🔒		Hard
306	additive-number			Medium
307	range-sum-query-mutable	Cpp	📝	Medium
308	range-sum-query-2d-mutable	🔒		Hard
309	best-time-to-buy-and-sell-stock-with-cooldown			Medium
310	minimum-height-trees			Medium
311	sparse-matrix-multiplication	🔒		Medium
312	burst-balloons			Hard
313	super-ugly-number			Medium
314	binary-tree-vertical-order-traversal	🔒		Medium
315	count-of-smaller-numbers-after-self			Hard
316	remove-duplicate-letters			Hard
317	shortest-distance-from-all-buildings	🔒		Hard
318	maximum-product-of-word-lengths			Medium
319	bulb-switcher			Medium
320	generalized-abbreviation	🔒	📝	Medium
321	create-maximum-number			Hard
322	coin-change		📝	Medium
323	number-of-connected-components-in-an-undirected-graph	🔒		Medium
324	wiggle-sort-ii			Medium
325	maximum-size-subarray-sum-equals-k	🔒		Medium
326	power-of-three	Cpp	📝	Easy
327	count-of-range-sum			Hard
328	odd-even-linked-list		📝	Medium
329	longest-increasing-path-in-a-matrix		📝	Hard
330	patching-array		📝	Hard
331	verify-preorder-serialization-of-a-binary-tree			Medium
332	reconstruct-itinerary			Medium
333	largest-bst-subtree	🔒		Medium
334	increasing-triplet-subsequence			Medium
335	self-crossing			Hard
336	palindrome-pairs			Hard
337	house-robber-iii			Medium
338	counting-bits		📝	Medium
339	nested-list-weight-sum	🔒	📝	Easy
340	longest-substring-with-at-most-k-distinct-characters	🔒		Hard
341	flatten-nested-list-iterator			Medium
342	power-of-four			Easy
343	integer-break			Medium
344	reverse-string	Cpp		Easy
345	reverse-vowels-of-a-string	Cpp		Easy
346	moving-average-from-data-stream	🔒		Easy
347	top-k-frequent-elements			Medium
348	design-tic-tac-toe	🔒		Medium
349	intersection-of-two-arrays	Cpp		Easy
350	intersection-of-two-arrays-ii	Cpp		Easy
351	android-unlock-patterns	🔒	📝	Medium
352	data-stream-as-disjoint-intervals			Hard
353	design-snake-game	🔒		Medium
354	russian-doll-envelopes			Hard
355	design-twitter			Medium
356	line-reflection	🔒		Medium
357	count-numbers-with-unique-digits			Medium
358	rearrange-string-k-distance-apart	🔒		Hard
359	logger-rate-limiter	🔒		Easy
360	sort-transformed-array	🔒		Medium
361	bomb-enemy	🔒		Medium
362	design-hit-counter	🔒		Medium
363	max-sum-of-rectangle-no-larger-than-k			Hard
364	nested-list-weight-sum-ii	🔒		Medium
365	water-and-jug-problem			Medium
366	find-leaves-of-binary-tree	🔒		Medium
367	valid-perfect-square	Cpp		Easy
368	largest-divisible-subset			Medium
369	plus-one-linked-list	🔒		Medium
370	range-addition	🔒	📝	Medium
371	sum-of-two-integers			Easy
372	super-pow			Medium
373	find-k-pairs-with-smallest-sums			Medium
374	guess-number-higher-or-lower		📝	Easy
375	guess-number-higher-or-lower-ii		📝	Medium
376	wiggle-subsequence		📝	Medium
377	combination-sum-iv			Medium
378	kth-smallest-element-in-a-sorted-matrix			Medium
379	design-phone-directory	🔒		Medium
380	insert-delete-getrandom-o1			Medium
381	insert-delete-getrandom-o1-duplicates-allowed			Hard
382	linked-list-random-node			Medium
383	ransom-note			Easy
384	shuffle-an-array			Medium
385	mini-parser			Medium
386	lexicographical-numbers			Medium
387	first-unique-character-in-a-string	Cpp		Easy
388	longest-absolute-file-path			Medium
389	find-the-difference	Cpp		Easy
390	elimination-game			Medium
391	perfect-rectangle			Hard
392	is-subsequence			Medium
393	utf-8-validation			Medium
394	decode-string			Medium
395	longest-substring-with-at-least-k-repeating-characters			Medium
396	rotate-function			Medium
397	integer-replacement			Medium
398	random-pick-index			Medium
399	evaluate-division			Medium
400	nth-digit			Easy
401	binary-watch			Easy
402	remove-k-digits			Medium
403	frog-jump		📝	Hard
404	sum-of-left-leaves	Cpp		Easy
405	convert-a-number-to-hexadecimal			Easy
406	queue-reconstruction-by-height			Medium
407	trapping-rain-water-ii			Hard
408	valid-word-abbreviation	🔒		Easy
409	longest-palindrome	Cpp		Easy
410	split-array-largest-sum			Hard
411	minimum-unique-word-abbreviation	🔒		Hard
412	fizz-buzz	Cpp		Easy
413	arithmetic-slices		📝	Medium
414	third-maximum-number			Easy
415	add-strings			Easy
416	partition-equal-subset-sum			Medium
417	pacific-atlantic-water-flow			Medium
418	sentence-screen-fitting	🔒		Medium
419	battleships-in-a-board			Medium
420	strong-password-checker			Hard
421	maximum-xor-of-two-numbers-in-an-array			Medium
422	valid-word-square	🔒		Easy
423	reconstruct-original-digits-from-english	Cpp		Medium
424	longest-repeating-character-replacement			Medium
425	word-squares	🔒		Hard
432	all-oone-data-structure			Hard
434	number-of-segments-in-a-string			Easy
435	non-overlapping-intervals		📝	Medium
436	find-right-interval		📝	Medium
437	path-sum-iii			Easy
438	find-all-anagrams-in-a-string			Easy
439	ternary-expression-parser	🔒		Medium
440	k-th-smallest-in-lexicographical-order			Hard
441	arranging-coins	Cpp		Easy
442	find-all-duplicates-in-an-array			Medium
444	sequence-reconstruction	🔒		Medium
445	add-two-numbers-ii			Medium
446	arithmetic-slices-ii-subsequence			Hard
447	number-of-boomerangs			Easy
448	find-all-numbers-disappeared-in-an-array			Easy
449	serialize-and-deserialize-bst			Medium
450	delete-node-in-a-bst			Medium
451	sort-characters-by-frequency	Cpp		Medium
452	minimum-number-of-arrows-to-burst-balloons			Medium
453	minimum-moves-to-equal-array-elements	Cpp	📝	Easy
454	4sum-ii	Cpp		Medium
455	assign-cookies			Easy
456	132-pattern		📝	Medium
459	repeated-substring-pattern			Easy
460	lfu-cache			Hard
461	hamming-distance	Cpp		Easy
462	minimum-moves-to-equal-array-elements-ii	Cpp	📝	Medium
463	island-perimeter	Cpp		Easy
464	can-i-win			Medium
465	optimal-account-balancing	🔒		Hard
466	count-the-repetitions		📝	Hard
467	unique-substrings-in-wraparound-string			Medium
468	validate-ip-address			Medium
469	convex-polygon	🔒		Medium
471	encode-string-with-shortest-length	🔒		Hard
472	concatenated-words			Hard
473	matchsticks-to-square			Medium
474	ones-and-zeroes		📝	Medium
475	heaters			Easy
476	number-complement	Cpp		Easy
477	total-hamming-distance		📝	Medium
479	largest-palindrome-product			Easy
480	sliding-window-median		📝	Hard
481	magical-string			Medium
482	license-key-formatting	Cpp		Medium
483	smallest-good-base			Hard
484	find-permutation	🔒	📝	Medium
485	max-consecutive-ones	Cpp		Easy
486	predict-the-winner		📝	Medium
487	max-consecutive-ones-ii	🔒		Medium
488	zuma-game			Hard
490	the-maze	🔒	📝	Medium
491	increasing-subsequences			Medium
492	construct-the-rectangle	Cpp		Easy
493	reverse-pairs		📝	Hard
494	target-sum		📝	Medium
495	teemo-attacking			Medium
496	next-greater-element-i		📝	Easy
498	diagonal-traverse			Medium
499	the-maze-iii	🔒		Hard
500	keyboard-row	Cpp		Easy
501	find-mode-in-binary-search-tree			Easy
502	ipo			Hard
503	next-greater-element-ii		📝	Medium
504	base-7			Easy
505	the-maze-ii	🔒	📝	Medium
506	relative-ranks			Easy
507	perfect-number		📝	Easy
508	most-frequent-subtree-sum			Medium
513	find-bottom-left-tree-value			Medium
514	freedom-trail			Hard
515	find-largest-value-in-each-tree-row			Medium
516	longest-palindromic-subsequence			Medium
517	super-washing-machines			Hard
520	detect-capital	Cpp		Easy
521	longest-uncommon-subsequence-i		📝	Easy
522	longest-uncommon-subsequence-ii		📝	Medium
523	continuous-subarray-sum		📝	Medium
524	longest-word-in-dictionary-through-deleting		📝	Medium
525	contiguous-array	Cpp	📝	Medium
526	beautiful-arrangement	Cpp	📝	Medium
527	word-abbreviation	🔒		Hard
529	minesweeper			Medium
530	minimum-absolute-difference-in-bst			Easy
531	lonely-pixel-i	🔒		Medium
532	k-diff-pairs-in-an-array			Easy
533	lonely-pixel-ii	🔒		Medium
535	encode-and-decode-tinyurl		📝	Medium
536	construct-binary-tree-from-string	🔒		Medium
537	complex-number-multiplication		📝	Medium
538	convert-bst-to-greater-tree			Easy
539	minimum-time-difference			Medium
540	single-element-in-a-sorted-array	Cpp		Medium
541	reverse-string-ii			Easy
542	01-matrix		📝	Medium
543	diameter-of-binary-tree			Easy
544	output-contest-matches	🔒		Medium
545	boundary-of-binary-tree	🔒	📝	Medium
546	remove-boxes		📝	Hard
547	friend-circles		📝	Medium
548	split-array-with-equal-sum	🔒	📝	Medium
549	binary-tree-longest-consecutive-sequence-ii	🔒	📝	Medium
551	student-attendance-record-i	Cpp	📝	Easy
552	student-attendance-record-ii		📝	Hard
553	optimal-division		📝	Medium
554	brick-wall		📝	Medium
555	split-concatenated-strings	🔒	📝	Medium
556	next-greater-element-iii		📝	Medium
557	reverse-words-in-a-string-iii	Cpp	📝	Easy
560	subarray-sum-equals-k		📝	Medium
561	array-partition-i	Cpp	📝	Easy
562	longest-line-of-consecutive-one-in-matrix	🔒	📝	Medium
563	binary-tree-tilt		📝	Easy
564	find-the-closest-palindrome		📝	Hard
566	reshape-the-matrix		📝	Easy
567	permutation-in-string		📝	Medium
568	maximum-vacation-days	🔒	📝	Hard
572	subtree-of-another-tree		📝	Easy
573	squirrel-simulation	🔒	📝	Medium
575	distribute-candies		📝	Easy
576	out-of-boundary-paths		📝	Medium
581	shortest-unsorted-continuous-subarray		📝	Easy
582	kill-process	🔒	📝	Medium
583	delete-operation-for-two-strings		📝	Medium
587	erect-the-fence		📝	Hard
588	design-in-memory-file-system	🔒	📝	Hard
591	tag-validator		📝	Hard
592	fraction-addition-and-subtraction		📝	Medium
593	valid-square		📝	Medium
594	longest-harmonious-subsequence		📝	Easy
598	range-addition-ii		📝	Easy
599	minimum-index-sum-of-two-lists		📝	Easy
600	non-negative-integers-without-consecutive-ones		📝	Hard
604	design-compressed-string-iterator	🔒	📝	Easy
605	can-place-flowers		📝	Easy
606	construct-string-from-binary-tree		📝	Easy
609	find-duplicate-file-in-system		📝	Medium
611	valid-triangle-number		📝	Medium
616	add-bold-tag-in-string	🔒	📝	Medium
617	merge-two-binary-trees		📝	Easy
621	task-scheduler		📝	Medium
623	add-one-row-to-tree		📝	Medium
624	maximum-distance-in-arrays	🔒	📝	Easy
625	minimum-factorization	🔒	📝	Medium
628	maximum-product-of-three-numbers		📝	Easy
629	k-inverse-pairs-array		📝	Hard
630	course-schedule-iii		📝	Hard
631	design-excel-sum-formula	🔒	📝	Hard
632	smallest-range		📝	Hard
633	sum-of-square-numbers		📝	Easy
634	find-the-derangement-of-an-array	🔒	📝	Medium
635	design-log-storage-system	🔒	📝	Medium
636	exclusive-time-of-functions		📝	Medium
637	average-of-levels-in-binary-tree		📝	Easy
638	shopping-offers		📝	Medium
639	decode-ways-ii		📝	Hard
640	solve-the-equation		📝	Medium
642	design-search-autocomplete-system	🔒	📝	Hard
643	maximum-average-subarray-i		📝	Easy
644	maximum-average-subarray-ii	🔒	📝	Hard
645	set-mismatch		📝	Easy
646	maximum-length-of-pair-chain			Medium
647	palindromic-substrings			Medium
648	replace-words			Medium
649	dota2-senate			Medium
650	2-keys-keyboard			Medium
651	4-keys-keyboard	🔒		Medium
652	find-duplicate-subtrees			Medium
653	two-sum-iv-input-is-a-bst		📝	Easy
654	maximum-binary-tree		📝	Medium
655	print-binary-tree		📝	Medium
656	coin-path	🔒	📝	Hard
657	judge-route-circle			Easy
658	find-k-closest-elements		📝	Medium
659	split-array-into-consecutive-subsequences			Medium
660	remove-9	🔒		Hard
661	image-smoother			Easy
662	maximum-width-of-binary-tree			Medium
663	equal-tree-partition	🔒		Medium
664	strange-printer			Hard
665	non-decreasing-array		📝	Easy
666	path-sum-iv	🔒		Medium
667	beautiful-arrangement-ii		📝	Medium
668	kth-smallest-number-in-multiplication-table		📝	Hard
669	trim-a-binary-search-tree		📝	Easy
670	maximum-swap		📝	Medium
671	second-minimum-node-in-a-binary-tree		📝	Easy
672	bulb-switcher-ii			Medium
673	number-of-longest-increasing-subsequence			Medium
674	longest-continuous-increasing-subsequence			Easy
675	cut-off-trees-for-golf-event			Hard
676	implement-magic-dictionary			Medium
677	map-sum-pairs		📝	Medium
678	valid-parenthesis-string		📝	Medium
679	24-game		📝	Hard
680	valid-palindrome-ii		📝	Easy
681	next-closest-time		📝	Medium
682	baseball-game		📝	Easy
683	k-empty-slots		📝	Hard
684	redundant-connection		📝	Medium
685	redundant-connection-ii			Hard
686	repeated-string-match		📝	Easy
687	longest-univalue-path		📝	Easy
688	knight-probability-in-chessboard		📝	Medium
689	maximum-sum-of-3-non-overlapping-subarrays		📝	Hard
690	employee-importance			Easy