recursion Problems | Design Gurus

Algorithms

recursion

111 problems

#	Title	Acceptance	Difficulty
1	Reverse Vowels (easy) string two pointers array +2 more	44.2%	easy
2	Valid Anagram (easy) sorting recursion hash map +1 more	38.3%	easy
3	Sqrt (medium) binary search recursion	15.3%	Med.
4	Find Non-Duplicate Number Instances (easy) array two pointers sorting +3 more	42.5%	easy
5	Squaring a Sorted Array (easy) array sorting two pointers +3 more	35.5%	easy
6	Problem Challenge 1: Quadruple Sum to Target (medium) sorting two pointers recursion +1 more	17.3%	Med.
7	Middle of the LinkedList (easy) linked list fast and slow pointers two pointers +3 more	59.9%	easy
8	Happy Number (medium) recursion linked list hash map	47.2%	Med.
9	Problem Challenge 1: Palindrome LinkedList (medium) linked list recursion doubly linked list	28.9%	Med.
10	Problem Challenge 2: Rearrange a LinkedList (medium) linked list two pointers recursion	56.3%	Med.
11	Problem Challenge 3: Cycle in a Circular Array (hard) array graph algorithms recursion +1 more	17.2%	hard
12	Problem Challenge 4: Words Concatenation (hard) string hash map two pointers +2 more	23.2%	hard
13	Cyclic Sort (easy) sorting cyclic sort array +1 more	48.3%	easy
14	Find the Duplicate Number (easy) array sorting two pointers +2 more	49.1%	easy
15	Problem Challenge 2: Find the Smallest Missing Positive Number (medium) array sorting recursion +3 more	28.8%	Med.
16	Problem Challenge 3: Find the First K Missing Positive Numbers (hard) array sorting recursion +2 more	16.7%	hard
17	Reverse a LinkedList (easy) linked list recursion sorting +4 more	80.1%	easy
18	Reverse a Sub-list (medium) linked list linked list reversal recursion +2 more	31.4%	Med.
19	Reverse every K-element Sub-list (medium) linked list recursion	53.1%	Med.
20	Problem Challenge 1: Reverse alternating K-element Sub-list (medium) linked list recursion	51.9%	Med.
21	Problem Challenge 2: Rotate a LinkedList (medium) linked list doubly linked list recursion +2 more	22.8%	Med.
22	Problem 1: Balanced Parentheses (easy) stack string depth-first search +1 more	30.1%	easy
23	Problem 5: Sorting a Stack (easy) sorting stack recursion	69.7%	easy
24	Remove Nodes From Linked List (easy) linked list linked list reversal recursion +1 more	41.9%	easy
25	Remove All Adjacent Duplicates In String (easy) stack string array +1 more	58.6%	easy
26	Remove All Adjacent Duplicates in String II (medium) string stack recursion +2 more	37.0%	Med.
27	Reverse Level Order Traversal (easy) breadth-first search binary tree queue +1 more	89.2%	easy
28	Maximum Width of Binary Tree (medium) binary tree breadth-first search tree depth first search +3 more	32.1%	Med.
29	Zigzag Traversal (medium) binary tree breadth-first search level order traversal +3 more	64.0%	Med.
30	Reverse Level Order Traversal (easy) breadth-first search binary tree queue +1 more	89.2%	easy
31	Zigzag Traversal (medium) binary tree breadth-first search level order traversal +3 more	64.0%	Med.
32	Minimum Depth of a Binary Tree (easy) binary tree breadth-first search depth-first search +1 more	21.5%	easy
33	Binary Tree Path Sum (easy) binary tree depth-first search recursion +1 more	38.3%	easy
34	All Paths for a Sum (medium) binary tree depth-first search recursion +2 more	56.9%	Med.
35	Sum of Path Numbers (medium) binary tree recursion depth-first search	69.0%	Med.
36	Path With Given Sequence (medium) binary tree recursion depth-first search +1 more	25.9%	Med.
37	Count Paths for a Sum (medium) binary tree depth-first search recursion +2 more	24.5%	Med.
38	Problem Challenge 1: Tree Diameter (medium) binary tree tree depth first search recursion +1 more	59.2%	Med.
39	Problem Challenge 2: Path with Maximum Sum (hard) binary tree tree depth first search recursion +2 more	17.7%	hard
40	Find if Path Exists in Graph(easy) graph breadth-first search depth-first search +2 more	42.8%	easy
41	Solution: Find if Path Exists in Graph(easy) graph depth-first search recursion	0.0%	easy
42	Number of Provinces (medium) graph depth-first search union-find +3 more	41.5%	Med.
43	Find Eventual Safe States (medium) graph depth-first search breadth-first search +2 more	64.2%	Med.
44	Solution: Minimum Number of Vertices to Reach All Nodes(medium) graph algorithms topological sort depth-first search +2 more	0.0%	Med.
45	Number of Islands (easy) matrix graph matrix traversal +4 more	49.3%	easy
46	Biggest Island (easy) matrix breadth-first search depth-first search +4 more	47.4%	easy
47	Flood Fill (easy) breadth-first search depth-first search recursion +3 more	38.4%	easy
48	Number of Closed Islands (easy) graph matrix traversal breadth-first search +2 more	44.0%	easy
49	Problem Challenge 2 (medium) graph matrix breadth-first search +3 more	62.6%	Med.
50	Problem Challenge 3 (medium) graph depth-first search matrix +1 more	19.1%	Med.
51	Subsets (easy) subsets backtracking array +1 more	60.3%	easy
52	Subsets With Duplicates (easy) subsets backtracking recursion	40.3%	easy
53	Permutations (medium) recursion backtracking array +2 more	58.8%	Med.
54	String Permutations by changing case (medium) recursion backtracking string +2 more	56.7%	Med.
55	Balanced Parentheses (hard) backtracking recursion string	27.9%	hard
56	Unique Generalized Abbreviations (hard) backtracking recursion string +2 more	70.3%	hard
57	Problem Challenge 1: Evaluate Expression (hard) recursion divide and conquer dynamic programming	67.4%	hard
58	Problem Challenge 2: Structurally Unique Binary Search Trees (hard) binary search tree binary tree recursion +2 more	30.1%	hard
59	Problem Challenge 3: Count of Structurally Unique Binary Search Trees (hard) binary search tree dynamic programming recursion +2 more	34.3%	hard
60	Order-agnostic Binary Search (easy) binary search sorting array +1 more	32.7%	easy
61	Ceiling of a Number (medium) binary search array sorting +1 more	23.7%	Med.
62	Next Letter (medium) binary search array string +1 more	36.8%	Med.
63	Search in a Sorted Infinite Array (medium) binary search array recursion	33.7%	Med.
64	Minimum Difference Element (medium) binary search sorting array +2 more	24.0%	Med.
65	Problem Challenge 2: Search in Rotated Array (medium) binary search array sorting +1 more	23.0%	Med.
66	Problem Challenge 3: Rotation Count (medium) binary search sorting array +1 more	24.2%	Med.
67	Problem Challenge 3: Frequency Stack (hard) stack hash map priority queue +2 more	40.0%	hard
68	Valid Palindrome II (easy) string recursion two pointers +1 more	33.1%	easy
69	Minimum Add to Make Parentheses Valid (medium) string stack recursion +2 more	48.3%	Med.
70	Equal Subset Sum Partition (medium) dynamic programming recursion greedy algorithm +2 more	42.8%	Med.
71	Subset Sum (medium) dynamic programming recursion subsets +1 more	35.0%	Med.
72	Minimum Subset Sum Difference (hard) dynamic programming recursion greedy algorithm +3 more	50.7%	hard
73	Problem Challenge 1: Count of Subset Sum (hard) subsets dynamic programming recursion +2 more	55.6%	hard
74	Problem Challenge 2: Target Sum (hard) dynamic programming recursion backtracking +1 more	44.6%	hard
75	Combination Sum (medium) backtracking recursion array +2 more	46.3%	Med.
76	Word Search (medium) depth-first search backtracking graph +2 more	28.6%	Med.
77	Factor Combinations (medium) recursion backtracking divide and conquer +1 more	36.3%	Med.
78	Split a String Into the Max Number of Unique Substrings (medium) string backtracking recursion +2 more	44.3%	Med.
79	Sudoku Solver (hard) backtracking recursion	74.3%	hard
80	Design Add and Search Words Data Structure (medium) trie string depth-first search +3 more	35.5%	Med.
81	Extra Characters in a String (medium) string dynamic programming recursion +1 more	53.0%	Med.
82	Topological Sort (medium) topological sort graph algorithms recursion +3 more	25.9%	Med.
83	Tasks Scheduling (medium) graph algorithms topological sort graph +2 more	46.4%	Med.
84	Tasks Scheduling Order (medium) graph algorithms topological sort recursion +2 more	47.0%	Med.
85	All Tasks Scheduling Orders (hard) topological sort graph algorithms graph +2 more	20.0%	hard
86	Problem Challenge 1: Reconstructing a Sequence (hard) graph algorithms topological sort graph +1 more	31.9%	hard
87	Number of Provinces (medium) graph depth-first search union-find +3 more	41.5%	Med.
88	Is Graph Bipartite? (medium) graph breadth-first search depth-first search +2 more	37.5%	Med.
89	Path With Minimum Effort (medium) graph algorithms breadth-first search depth-first search +3 more	40.8%	Med.
90	Left and Right Sum Differences (easy) array prefix sum recursion +1 more	67.0%	easy
91	Same Tree (medium) binary tree binary search tree recursion +2 more	47.1%	Med.
92	Invert Binary Tree (medium) binary tree recursion depth-first search +1 more	77.7%	Med.
93	Binary Search Tree Iterator (medium) binary search tree recursion breadth-first search +2 more	90.0%	Med.
94	Valid Perfect Square (easy) binary search recursion sorting	21.8%	easy
95	Subtree of Another Tree (easy) binary tree recursion breadth-first search +2 more	35.4%	easy
96	Decode String (medium) recursion string backtracking +1 more	45.2%	Med.
97	Maximum Product Subarray (medium) dynamic programming array greedy algorithm +1 more	22.2%	Med.
98	Remove Nth Node From End of List (medium) linked list two pointers recursion +1 more	30.1%	Med.
99	Find Minimum in Rotated Sorted Array (medium) binary search array sorting +2 more	26.0%	Med.
100	Validate Binary Search Tree (medium) binary search tree recursion binary tree +1 more	28.3%	Med.