recursion Problems | Design Gurus

Algorithms

recursion

109 problems

#	Title	Acceptance	Difficulty
1	Valid Palindrome (easy) string array two pointers +1 more	22.6%	easy
2	Valid Anagram (easy) string hash map sorting +2 more	38.4%	easy
3	Sqrt (medium) binary search recursion sorting	15.4%	Med.
4	Find Non-Duplicate Number Instances (easy) array sorting two pointers +1 more	42.5%	easy
5	Squaring a Sorted Array (easy) array sorting two pointers +3 more	35.6%	easy
6	Triplet Sum to Zero (medium) sorting two pointers array +3 more	22.2%	Med.
7	Problem Challenge 1: Quadruple Sum to Target (medium) sorting two pointers recursion +1 more	17.3%	Med.
8	Happy Number (medium) recursion linked list hash map	47.2%	Med.
9	Problem Challenge 1: Palindrome LinkedList (medium) linked list recursion two pointers	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) graph array two pointers +1 more	17.3%	hard
12	Longest Substring with Same Letters after Replacement (hard) string sliding window recursion +1 more	29.9%	hard
13	Problem Challenge 4: Words Concatenation (hard) string hash map array +3 more	23.2%	hard
14	Problem Challenge 1: Minimum Meeting Rooms (hard) merge intervals array sorting +1 more	25.8%	hard
15	Find all Missing Numbers (easy) array cyclic sort sorting +1 more	54.3%	easy
16	Problem Challenge 2: Find the Smallest Missing Positive Number (medium) array sorting recursion +3 more	28.9%	Med.
17	Problem Challenge 3: Find the First K Missing Positive Numbers (hard) array sorting recursion +2 more	16.8%	hard
18	Reverse a LinkedList (easy) linked list recursion sorting +4 more	80.1%	easy
19	Reverse a Sub-list (medium) linked list linked list reversal two pointers +1 more	31.4%	Med.
20	Reverse every K-element Sub-list (medium) linked list array recursion +1 more	53.1%	Med.
21	Problem Challenge 1: Reverse alternating K-element Sub-list (medium) linked list linked list reversal recursion +1 more	51.7%	Med.
22	Problem Challenge 2: Rotate a LinkedList (medium) linked list recursion simulation	22.9%	Med.
23	Problem 1: Balanced Parentheses (easy) stack queue array +2 more	30.1%	easy
24	Problem 3: Decimal to Binary Conversion (medium) array string recursion	46.7%	Med.
25	Problem 5: Sorting a Stack (easy) stack sorting recursion	69.7%	easy
26	Problem 6: Simplify Path (medium) string stack recursion	25.2%	Med.
27	Remove Nodes From Linked List (easy) linked list linked list reversal recursion +1 more	41.9%	easy
28	Remove All Adjacent Duplicates In String (easy) stack string backtracking +1 more	58.6%	easy
29	Remove All Adjacent Duplicates in String II (medium) stack recursion string +1 more	37.1%	Med.
30	Sum of Subarray Minimums (medium) subsets array stack +3 more	67.6%	Med.
31	Reverse Level Order Traversal (easy) breadth-first search binary tree queue +1 more	89.2%	easy
32	Zigzag Traversal (medium) binary tree breadth-first search level order traversal +3 more	64.1%	Med.
33	Minimum Depth of a Binary Tree (easy) binary tree breadth-first search depth-first search +1 more	21.5%	easy
34	Maximum Width of Binary Tree (medium) binary tree breadth-first search tree depth first search +3 more	32.1%	Med.
35	Binary Tree Path Sum (easy) binary tree depth-first search recursion	38.3%	easy
36	All Paths for a Sum (medium) binary tree recursion depth-first search	56.9%	Med.
37	Sum of Path Numbers (medium) binary tree recursion depth-first search	69.0%	Med.
38	Path With Given Sequence (medium) binary tree recursion depth-first search +1 more	25.9%	Med.
39	Count Paths for a Sum (medium) binary tree recursion depth-first search +2 more	24.5%	Med.
40	Problem Challenge 1: Tree Diameter (medium) binary tree graph algorithms recursion +2 more	59.3%	Med.
41	Problem Challenge 2: Path with Maximum Sum (hard) binary tree graph algorithms recursion +1 more	17.7%	hard
42	Solution: Find if Path Exists in Graph (easy) graph algorithms depth-first search recursion +2 more	0.0%	easy
43	Find Eventual Safe States (medium) graph depth-first search breadth-first search +2 more	64.2%	Med.
44	Number of Islands (easy) graph breadth-first search depth-first search +3 more	49.4%	easy
45	Biggest Island (easy) graph matrix depth-first search +2 more	47.5%	easy
46	Flood Fill (easy) breadth-first search depth-first search recursion +2 more	38.5%	easy
47	Number of Closed Islands (easy) graph matrix traversal breadth-first search +2 more	44.1%	easy
48	Problem Challenge 1 (easy) matrix recursion depth-first search	27.4%	easy
49	Problem Challenge 2 (medium) graph breadth-first search depth-first search +4 more	62.6%	Med.
50	Problem Challenge 3 (medium) graph matrix depth-first search +1 more	19.1%	Med.
51	Subsets (easy) subsets backtracking array +1 more	60.4%	easy
52	Permutations (medium) recursion backtracking array +2 more	58.9%	Med.
53	String Permutations by changing case (medium) recursion backtracking string +2 more	56.7%	Med.
54	Balanced Parentheses (hard) backtracking string recursion	28.0%	hard
55	Unique Generalized Abbreviations (hard) string backtracking recursion +1 more	70.2%	hard
56	Problem Challenge 1: Evaluate Expression (hard) recursion divide and conquer dynamic programming	67.2%	hard
57	Problem Challenge 2: Structurally Unique Binary Search Trees (hard) binary tree binary search tree recursion +2 more	30.1%	hard
58	Problem Challenge 3: Count of Structurally Unique Binary Search Trees (hard) binary search tree dynamic programming recursion +2 more	34.4%	hard
59	Order-agnostic Binary Search (easy) binary search sorting array +1 more	32.8%	easy
60	Next Letter (medium) binary search array recursion	36.9%	Med.
61	Search in a Sorted Infinite Array (medium) binary search array recursion +1 more	33.7%	Med.
62	Bitonic Array Maximum (easy) binary search array sorting +1 more	35.0%	easy
63	Problem Challenge 1: Search Bitonic Array (medium) binary search array recursion +1 more	31.1%	Med.
64	Problem Challenge 2: Search in Rotated Array (medium) binary search array recursion +1 more	23.1%	Med.
65	Problem Challenge 3: Rotation Count (medium) binary search array recursion +1 more	24.3%	Med.
66	Problem Challenge 1: Flip and Invert an Image (hard) array matrix two pointers +1 more	58.3%	hard
67	Problem Challenge 3: Frequency Stack (hard) stack hash map priority queue +2 more	40.0%	hard
68	Valid Palindrome II (easy) string recursion backtracking +3 more	33.1%	easy
69	Minimum Add to Make Parentheses Valid (medium) string stack recursion +2 more	48.3%	Med.
70	0/1 Knapsack (medium) greedy algorithm 0/1 knapsack dynamic programming +1 more	43.8%	Med.
71	Equal Subset Sum Partition (medium) dynamic programming recursion greedy algorithm +2 more	42.7%	Med.
72	Subset Sum (medium) dynamic programming recursion subsets +1 more	35.0%	Med.
73	Minimum Subset Sum Difference (hard) dynamic programming recursion greedy algorithm +3 more	50.7%	hard
74	Problem Challenge 1: Count of Subset Sum (hard) dynamic programming recursion subsets	55.6%	hard
75	Problem Challenge 2: Target Sum (hard) dynamic programming recursion backtracking +2 more	44.6%	hard
76	Combination Sum (medium) backtracking recursion dynamic programming	46.4%	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	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 array dynamic programming +3 more	53.0%	Med.
82	Topological Sort (medium) topological sort graph algorithms recursion +1 more	26.0%	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	47.1%	Med.
85	All Tasks Scheduling Orders (hard) graph topological sort recursion +1 more	20.0%	hard
86	Alien Dictionary (hard) graph topological sort depth-first search +2 more	45.7%	hard
87	Problem Challenge 1: Reconstructing a Sequence (hard) graph algorithms topological sort recursion +2 more	31.9%	hard
88	Is Graph Bipartite? (medium) graph breadth-first search depth-first search +2 more	37.5%	Med.
89	Left and Right Sum Differences (easy) array prefix sum recursion +1 more	67.0%	easy
90	Same Tree (medium) binary tree binary search tree recursion +2 more	47.2%	Med.
91	Invert Binary Tree (medium) binary tree recursion tree depth first search +1 more	77.6%	Med.
92	Binary Search Tree Iterator (medium) binary search tree recursion breadth-first search +2 more	89.6%	Med.
93	Valid Perfect Square (easy) binary search recursion sorting	21.9%	easy
94	Subtree of Another Tree (easy) binary tree recursion breadth-first search +2 more	35.5%	easy
95	Decode String (medium) recursion string backtracking +1 more	45.2%	Med.
96	Maximum Product Subarray (medium) dynamic programming array greedy algorithm +1 more	22.3%	Med.
97	Remove Nth Node From End of List (medium) linked list two pointers recursion +1 more	30.0%	Med.
98	Find Minimum in Rotated Sorted Array (medium) binary search array sorting +2 more	26.0%	Med.
99	Validate Binary Search Tree (medium) binary tree binary search tree recursion +1 more	28.3%	Med.
100	Construct Binary Tree from Preorder and Inorder Traversal (medium) binary tree binary search tree recursion +4 more	52.7%	Med.