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⬇️ No.	Problem Title	Organization	Solution	Algorithm	Time Complexity
218	206. Reverse Linked List	LeetCode	218.py	linked-list	$$O(n)$$
217 💜	205. Isomorphic Strings	LeetCode	217.py	string	$$O(n)$$
216	203. Remove Linked List Elements	LeetCode	216.py	linked-list	$$O(n)$$
215	202. Happy Number	LeetCode	215.py	math	$$O(1)$$
214	197. Rising Temperature	LeetCode	214.sql	sql	$$O(n)$$
213	196. Delete Duplicate Emails	LeetCode	213.sql	sql	$$O(n)$$
212	195. Tenth Line	LeetCode	212.sh	shell	$$O(n)$$
211	193. Valid Phone Numbers	LeetCode	211.sh	shell	$$O(n)$$
210	191. Number of 1 Bits	LeetCode	210.py	bitwise	$$O(\log n)$$
209 💜	190. Reverse Bits	LeetCode	209.go	bitwise	$$O(1)$$
208	183. Customers Who Never Order	LeetCode	208.sql	sql	$$O(n)$$
207	182. Duplicate Emails	LeetCode	207.sql	sql	$$O(n)$$
206	181. Employees Earning More Than Their Managers	LeetCode	206.sql	sql	$$O(n)$$
205	175. Combine Two Tables	LeetCode	205.sql	sql	$$O(n)$$
204 💜	171. Excel Sheet Column Number	LeetCode	204.py	math	$$O(n)$$
203	169. Majority Element	LeetCode	203.py	sorting	$$O(n \log n)$$
202 💜	168. Excel Sheet Column Title	LeetCode	202.py	math	$$O(\log n)$$
201	160. Intersection of Two Linked Lists	LeetCode	201.py	linked-list	$$O(n + m)$$
200	145. Binary Tree Postorder Traversal	LeetCode	200.go	tree	$$O(n)$$
199	144. Binary Tree Preorder Traversal	LeetCode	199.py	tree	$$O(n)$$
198 ⭐	141. Linked List Cycle	LeetCode	198.py	linked-list	$$O(n)$$
197 ⭐	136. Single Number	LeetCode	197.ts	bitwise	$$O(n)$$
196	125. Valid Palindrome	LeetCode	196.js	string	$$O(n)$$
195 💜	121. Best Time to Buy and Sell Stock	LeetCode	195.go	array	$$O(n)$$
194	119. Pascal's Triangle II	LeetCode	194.py	array	$$O(2^n)$$
193	118. Pascal's Triangle	LeetCode	193.py	array	$$O(2^n)$$
192	112. Path Sum	LeetCode	192.py	tree	$$O(n)$$
191	111. Minimum Depth of Binary Tree	LeetCode	191.py	tree	$$O(n)$$
190 ⭐	110. Balanced Binary Tree	LeetCode	190.py	tree	$$O(n)$$
189	108. Convert Sorted Array to Binary Search Tree	LeetCode	189.py	tree	$$O(n)$$
188	104. Maximum Depth of Binary Tree	LeetCode	188.py	tree	$$O(n)$$
187	101. Symmetric Tree	LeetCode	187.py	tree	$$O(n)$$
186	100. Same Tree	LeetCode	186.py	tree	$$O(n)$$
185	94. Binary Tree Inorder Traversal	LeetCode	185.py	tree	$$O(n)$$
184	83. Remove Duplicates from Sorted List	LeetCode	184.py	linked-list	$$O(n)$$
183	70. Climbing Stairs	LeetCode	183.py	dp	$$O(n)$$
182	69. Sqrt(x)	LeetCode	182.py	binary-search	$$O(\log n)$$
181	67. Add Binary	LeetCode	181.py	string	$$O(n)$$
180	66. Plus One	LeetCode	180.py	array	$$O(n)$$
179	58. Length of Last Word	LeetCode	179.py	array	$$O(n)$$
178	28. Find the Index of the First Occurrence in a String	LeetCode	178.py	string	$$O(n \cdot m)$$
177	27. Remove Element	LeetCode	177.py	2-pointers	$$O(n)$$
176	26. Remove Duplicates from Sorted Array	LeetCode	176.py	array	$$O(n)$$
175	2131. Longest Palindrome by Concatenating Two Letter Words	LeetCode	175.py	math	$$O(n)$$
174	2942. Find Words Containing Character	LeetCode	174.py	math	$$O(n \cdot max(length(word)))$$
173	3024. Type of Triangle	LeetCode	173.py	math	$$O(1)$$
172	75. Sort Colors	LeetCode	172.py	array	$$O(n)$$
171	3335. Total Characters in String After Transformations I	LeetCode	171.ts	array	$$O(max(n, t))$$
170	2094. Finding 3-Digit Even Numbers	LeetCode	170.ts	array	$$O(n^3)$$
169	1550. Three Consecutive Odds	LeetCode	169.ts	array	$$O(n)$$
168	3341. Find Minimum Time to Reach Last Room I	LeetCode	168.py	dijsktra	$$O(mn \cdot \log{mn})$$
167 ⭐	790. Domino and Tromino Tiling	LeetCode	167.py	dp	$$O(n)$$
166	1920. Build Array from Permutation	LeetCode	166.ts	logic	$$O(n)$$
165	1128. Number of Equivalent Domino Pairs	LeetCode	165.ts	logic	$$O(n)$$
164	1007. Minimum Domino Rotations For Equal Row	LeetCode	164.ts	logic	$$O(n)$$
163	838. Push Dominoes	LeetCode	163.py	logic	$$O(n)$$
162 ⭐	2071. Maximum Number of Tasks You Can Assign	LeetCode	162.py	binary-search	$$O(\max(nlogn, mlogm) + \min(m, n) \cdot \log_{2}{min(m, n)})$$
161	1399. Count Largest Group	LeetCode	161.ts	hash-map	$$O(n \cdot \log_{10}{n})$$
160	2799. Count Complete Subarrays in an Array	LeetCode	160.ts	sliding-window	$$O(n)$$
159	2845. Count of Interesting Subarrays	LeetCode	159.ts	prefix-sum	$$O(n)$$
158	1534. Count Good Triplets	LeetCode	158.ts	logic	$$O(n^3)$$
157	1295. Find Numbers with Even Number of Digits	LeetCode	157.ts	recursive	$$O(n \cdot \log_{10}{m})$$ with $m$ is the maximum value in the given array $nums$
156 ⭐	2962. Count Subarrays Where Max Element Appears at Least K Times	LeetCode	156.py	sliding-window	$$O(n)$$
155	2302. Count Subarrays With Score Less Than K	LeetCode	155.py	sliding-window	$$O(n)$$
154	3392. Count Subarrays of Length Three With a Condition	LeetCode	154.py	sliding-window	$$O(n)$$
153	1399. Count Largest Group	LeetCode	153.py	hashmap	$$O(nlogn)$$
152	38. Count and Say	LeetCode	152.py	backtracking	$$O(2^n)$$
151 ⭐	1922. Count Good Numbers	LeetCode	151.py	fast-exponentiation	$$O(logn)$$
150	3396. Minimum Number of Operations to Make Elements in Array Distinct	LeetCode	150.java	logic	$$O(n)$$
149	2843. Count Symmetric Integers	LeetCode	149.py	logic	$$O(n)$$
148	416. Partition Equal Subset Sum	LeetCode	148.py	dp	$$O(n^2)$$
147	368. Largest Divisible Subset	LeetCode	147.py	dp	$$O(n^2)$$
146	198. House Robber	LeetCode	146.py	dp	$$O(n)$$
145	1863. Sum of All Subset XOR Totals	LeetCode	145.py	backtracking	$$O(2^n)$$
144	1123. Lowest Common Ancestor of Deepest Leaves	LeetCode	144.py	dfs, backtracking	$$O(n)$$
143	2874. Maximum Value of an Ordered Triplet II	LeetCode	143.py	greedy	$$O(n)$$
142 ⭐	2140. Solving Questions With Brainpower	LeetCode	142.py	dp	$$O(n)$$
141 ⭐	763. Partition Labels	LeetCode	141.py	2-pointers	$$O(n)$$
140	2401. Longest Nice Subarray	LeetCode	140.py	sliding-window	$$O(n)$$
139	3191. Minimum Operations to Make Binary Array Elements Equal to One I	LeetCode	139.py	sliding-window	$$O(n)$$
138	3169. Count Days Without Meetings	LeetCode	138.py	sort	$$O(log(n))$$
137	2780. Minimum Index of a Valid Split	LeetCode	137.py	logic	$$O(n)$$
136	2033. Minimum Operations to Make a Uni-Value Grid	LeetCode	136.py	sort, math	$$O(n \cdot logn)$$
135	2685. Count the Number of Complete Components	LeetCode	135.py	dfs	$$O(n+mlogn) \text{ and } O(n+m)$$
134	1976. Number of Ways to Arrive at Destination	LeetCode	134.py	dijkstra	$$O((N + E)log(N))$$
133	2206. Divide Array Into Equal Pairs	LeetCode	133.java	logic	$$O(max(n, 500))$$
132 ⭐	2594. Minimum Time to Repair Cars	LeetCode	132.java	binary-search	$$O(n log(n))$$
131 ⭐	2560. House Robber IV	LeetCode	131.py	binary-search	$$O(n log(n))$$
130 ⭐	3356. Zero Array Transformation II	LeetCode	130.py	binary-search	$$O(n log(n))$$
129	2226. Maximum Candies Allocated to K Children	LeetCode	129.py	binary-search	$$O(n log(m))$$ with $m$ is the maximum value in the array $candies$, and $n$ is the length of $candies$
128	88. Merge Sorted Array	LeetCode	128.py	sort	$$O(log(n))$$
127	3306. Count of Substrings Containing Every Vowel and K Consonants II	LeetCode	127.py	slide-window	$$O(n)$$
126	2529. Maximum Count of Positive Integer and Negative Integer	LeetCode	126.py	logic	$$O(n)$$
125	1358. Number of Substrings Containing All Three Characters	LeetCode	125.py	slide-window	$$O(n)$$
124	3208. Alternating Groups II	LeetCode	124.js	2-pointers	$$O(n + k)$$
123	876. Middle of the Linked List	LeetCode	123.go	logic	$$O(n)$$
122	2379. Minimum Recolors to Get K Consecutive Black Blocks	LeetCode	122.go	logic	$$O(n)$$
121	2523. Closest Prime Numbers in Range	LeetCode	121.go	logic	$$O(n\cdot log(log(n)))$$
120	2965. Find Missing and Repeated Values	LeetCode	120.py	logic	$$O(n^2)$$
119	2579. Count Total Number of Colored Cells	LeetCode	119.go	logic	$$O(n / 2)$$
118	1780. Check if Number is a Sum of Powers of Three	LeetCode	118.js	logic	$$O(16)$$
117	2161. Partition Array According to Given Pivot	LeetCode	117.ts	logic	$$O(n)$$
116	2570. Merge Two 2D Arrays by Summing Values	LeetCode	116.js	logic	$$O(m + n)$$
115	2460. Apply Operations to an Array	LeetCode	115.go	logic	$$O(n)$$
114 ⭐	1092. Shortest Common Supersequence	LeetCode	114.py	dp	$$O(n \cdot m)$$
113 ⭐	873. Length of Longest Fibonacci Subsequence	LeetCode	113.go	dp	$$O(n^2)$$
112 ⭐	1749. Maximum Absolute Sum of Any Subarray	LeetCode	112.py	greedy	$$O(n)$$
111 ⭐	1524. Number of Sub-arrays With Odd Sum	LeetCode	111.py	dp	$$O(n)$$
110	35. Search Insert Position	LeetCode	110.js	binary-search	$$O(log(n))$$
109	21. Merge Two Sorted Lists	LeetCode	109.java	logic	$$O(n)$$
108 ⭐	2467. Most Profitable Path in a Tree	LeetCode	108.py	dfs	$$O(n)$$
107 ⭐	889. Construct Binary Tree from Preorder and Postorder Traversal	LeetCode	107.py	bin-tree, back-tracking	$$O(n^2)$$
106 ⭐	1028. Recover a Tree From Preorder Traversal	LeetCode	106.py	bin-tree, back-tracking	$$O(n)$$
105	3325. Count Substrings With K-Frequency Characters I	LeetCode	105.py	logic	$$O(n)$$
104	1261. Find Elements in a Contaminated Binary Tree	LeetCode	104.py	back-tracking	$$O(n)$$
103	1980. Find Unique Binary String	LeetCode	103.py	back-tracking	$$O(n!)$$
102	1415. The k-th Lexicographical String of All Happy Strings of Length n	LeetCode	102.py	back-tracking, set, sort	$$O(n!)$$
101	2375. Construct Smallest Number From DI String	LeetCode	101.py	back-tracking, set	$$O(n \cdot n!)$$
100	1079. Letter Tile Possibilities	LeetCode	100.py	back-tracking, set	$$O(n \cdot n!)$$
99	1718. Construct the Lexicographically Largest Valid Sequence	LeetCode	99.py	recursive
98	2698. Find the Punishment Number of an Integer	LeetCode	98.py	recursive
97	1352. Product of the Last K Numbers	LeetCode	97.py	logic
96	3066. Minimum Operations to Exceed Threshold Value II	LeetCode	96.py	heap
95	2342. Max Sum of a Pair With Equal Sum of Digits	LeetCode	95.py	logic
94	2816. Double a Number Represented as a Linked List	LeetCode	94.py	linked-list
93	1910. Remove All Occurrences of a Substring	LeetCode	93.py	stack
92	2739. Total Distance Traveled	LeetCode	92.py	logic
91	3289. The Two Sneaky Numbers of Digitville	LeetCode	91.py	logic
90	3174. Clear Digits	LeetCode	90.py	stack
89	2364. Count Number of Bad Pairs	LeetCode	89.py	logic, math
88	2349. Design a Number Container System	LeetCode	88.py	heap
87	10246 - Asterix and Obelix	UVA	87.py	floy-warshall
86	10171 - Meeting Prof. Miguel...	UVA	86.py	floy-warshall
85	278. First Bad Version	LeetCode	85.py	binary-search
84	ARBITRAG - Arbitrage	SPOJ	84.py	floy-warshall
83	515. Find Largest Value in Each Tree Row	LeetCode	83.py	sort, binary-tree
82	Monk's Business Day	HackerRank	82.py	bellman
81	UCV2013B - Alice in Amsterdam, I mean Wonderland	SPOJ	81.cpp	bellman
80	Extended Traffic	LightOJ	80.cpp	bellman
79	558 - Wormholes	UVA	79.py	bellman
78	TRAFFICN - Traffic Network	SPOJ	78.cpp	dijkstra
77	Commandos	LightOJ	77.cpp	dijkstra
76	10986 - Sending email	UVA	76.py	dijkstra
75	SHPATH - The Shortest Path	SPOJ	75.cpp	dijkstra
74	MICEMAZE - Mice and Maze	SPOJ	74.py	dijkstra
73	TRVCOST - Travelling cost	SPOJ	73.py	dijkstra
72	3043. Find the Length of the Longest Common Prefix	LeetCode	72.py	trie
71	3160. Find the Number of Distinct Colors Among the Balls	LeetCode	71.py	queue, dict
70	2239. Find Closest Number to Zero	LeetCode	70.py	logic
69	966. Vowel Spellchecker	LeetCode	69.py	logic
68	2576. Find the Maximum Number of Marked Indices	LeetCode	68.py	2-pointers, sort
67	3. Longest Substring Without Repeating Characters	LeetCode	67.py	2-pointers
66	4. Median of Two Sorted Arrays	LeetCode	66.py	sort
65	2. Add Two Numbers	LeetCode	65.py	linked-list
64	1726. Tuple with Same Product	LeetCode	64.py	sorting, 2-pointers, math
63	ALLIZWEL - ALL IZZ WELL	SPOJ	63.py	dfs
62	Bishu and his Girlfriend	HackerEarth	62.cpp	dfs
61	Maximum Level Sum of a Binary Tree	LeetCode	61.py	dfs
60	Minimum Absolute Difference in BST	LeetCode	60.py	dfs
59	Equal Row and Column Pairs	LeetCode	59.py	hash
58	Summary Ranges	LeetCode	58.py	logic
57	Longest Common Prefix	LeetCode	57.py	sort
56	Roman to Integer	LeetCode	56.py	logic
55	Palindrome Number	LeetCode	55.py	logic
54	Best Time to Buy and Sell Stock II	LeetCode	54.py	logic
53	Ransom Note	LeetCode	53.py	logic
52	Two Sum	LeetCode	52.py	logic
51	Roy and Trending Topics	HackerEarth	51.py	heap
50	Restaurant Rating	CodeChef	50.py	heap
49	QHEAP1	HackerRank	49.py	heap
48	Monk and Multiplication	HackerEarth	48.py	heap
47	11995 - I Can Guess the Data Structure!	UVA	47.py	heap, stack,queue
46	10954 - Add All	UVA	46.py	heap
45	LASTSHOT - THE LAST SHOT	SPOJ	45.go	dfs
44	BENEFACT - The Benefactor	SPOJ	44.py	dfs
43	CAM5 - prayatna PR	SPOJ	43.cpp	dfs
42	D. Lakes in Berland	Codeforces	42.py	dfs
41	1610 - Dudu Service Maker	UVA	41.py	dfs
40	C. Kefa and Park	Codeforces	40.py	bfs
39	Valid Parentheses	LeetCode	39.py	logic
38	C. Ice Cave	Codeforces	38.py	bfs
37	Breadth First Search: Shortest Reach	HackerRank	37.py	bfs
36	Dhoom 4	HackerEarth	36.py	bfs
35	Guilty Prince	LightOJ	35.py	bfs
34	MAKEMAZE - VALIDATE THE MAZE	SPOJ	34.py	bfs
33	UCV2013H - Slick	SPOJ	33.py	bfs
32	10901 - Ferry Loading III	UVA	32.cpp	queue
31	12207 - That is Your Queue	UVA	31.cpp	queue
30	10935 - Throwing cards away I	UVA	30.cpp	queue
29	ONP - Transform the Expression	SPOJ	29.cpp	stack
28	STPAR - Street Parade	SPOJ	28.cpp	stack
27	MMASS - Mass of Molecule	SPOJ	27.cpp	stack
26	Compilers and parsers	Codechef	26.cpp	greedy
25	B. Sort the Array	Codeforces	25.cpp	sort, logic, 2-pointers
24	B. Pasha and Tea	Codeforces	24.cpp	sort, logic
23	B. Eight Point Sets	Codeforces	23.cpp	sort, logic
22	B. Devu, the Dumb Guy	Codeforces	22.cpp	sort
21	A. Towers	Codeforces	21.cpp	logic
20	A. GukiZ and Contest	Codeforces	20.cpp	sort
19	A. Chores	Codeforces	19.cpp	sort
18	A. Business trip	Codeforces	18.cpp	sort
17	C. Alice, Bob and Chocolate	Codeforces	17.cpp	2-pointers
16	B. George and Round	Codeforces	16.cpp	2-pointers
15	B. Books	Codeforces	15.cpp	2-pointers
14	B. Balls Game	Codeforces	14.cpp	2-pointers
13	B. Array	Codeforces	13.cpp	2-pointers
12	B. Approximating a Constant Range	Codeforces	12.cpp	2-pointers
11	A. Sereja and Dima	Codeforces	11.cpp	logic
10	A. Dress'em in Vests!	Codeforces	10.cpp	logic
9	B. Passwords	Codeforces	9.cpp	math
8	B. Big Segment	Codeforces	8.cpp	logic
7	B. African Crossword	Codeforces	7.cpp	logic
6	A. Vitaly and Strings	Codeforces	6.cpp	logic
5	A. Arrays	Codeforces	5.cpp	sort
4	A. Bear and Game	Codeforces	4.cpp	logic
3	A. Night at the Museum	Codeforces	3.cpp	logic
2	A. Fashion in Berland	Codeforces	2.cpp	logic
1	A. Numbers	Codeforces	1.cpp	math