Core Pillars

Patterns

201

Algorithms

199

Data Structures

224

two pointers

42

fast and slow pointers

2

sliding window

15

merge intervals

5

cyclic sort

1

linked list reversal

2

stack

21

monotonic stack

6

hash map

42

level order traversal

13

tree breadth first search

5

tree depth first search

7

graph

27

matrix traversal

2

two heaps

2

subsets

7

bitwise xor

1

top k elements

7

k-way merge

7

greedy algorithm

44

0/1 knapsack

1

backtracking

27

trie

6

topological sort

8

union-find

4

prefix sum

8

counting

29

simulation

8

linear sorting

1

serialize and deserialize

1

clone

1

#

Title

Acceptance

Difficulty

1

Contains Duplicate (easy)
hash map
hash set
array
+2 more

55.5%

easy

2

string
array
hash map
+1 more

31.0%

easy

3

Reverse Vowels (easy)
string
two pointers
array
+2 more

44.2%

easy

4

string
two pointers

22.6%

easy

5

sorting
recursion
hash map
+1 more

38.4%

easy

6

array
string
two pointers
+3 more

27.8%

easy

7

array
counting
hash map

75.4%

easy

8

binary search
recursion

15.4%

Med.

9

two pointers
array
binary search
+1 more

42.4%

easy

10

array
two pointers
sorting
+3 more

42.5%

easy

11

array
sorting
two pointers
+3 more

35.5%

easy

12

array
sorting
two pointers

22.2%

Med.

13

sorting
array
greedy algorithm

12.2%

Med.

14

sorting
two pointers
array
+1 more

22.6%

Med.

15

two pointers
sorting
array
+1 more

29.6%

Med.

16

17.3%

Med.

17

16.8%

Med.

18

12.7%

Med.

19

64.5%

easy

20

linked list
fast and slow pointers
two pointers
+3 more

59.9%

easy

21

linked list
fast and slow pointers
graph algorithms

49.6%

Med.

22

recursion
linked list
hash map

47.2%

Med.

23

linked list
recursion
doubly linked list

28.9%

Med.

24

56.2%

Med.

25

array
graph algorithms
recursion
+1 more

17.2%

hard

26

sliding window
greedy algorithm
array
+1 more

46.3%

easy

27

sliding window
array
two pointers

19.7%

easy

28

28.0%

Med.

29

sliding window
array
two pointers
+1 more

39.5%

Med.

30

29.8%

hard

31

48.7%

hard

32

sliding window
string
hash map
+1 more

16.2%

hard

33

string
hash map
sliding window
+2 more

29.0%

hard

34

20.0%

hard

35

string
hash map
two pointers
+2 more

23.2%

hard

36

29.0%

hard

37

24.8%

hard

38

merge intervals
sorting
array
+1 more

31.3%

Med.

39

merge intervals
array
greedy algorithm

21.9%

Med.

40

merge intervals
two pointers
array

48.0%

Med.

41

merge intervals
sorting
greedy algorithm

28.1%

Med.

42

greedy algorithm
sorting
array
+1 more

25.8%

hard

43

sorting
greedy algorithm
data modeling

43.0%

hard

44

48.4%

hard

45

sorting
cyclic sort
array
+1 more

48.3%

easy

46

42.5%

easy

47

array
counting
sorting
+1 more

54.3%

easy

48

array
sorting
two pointers
+2 more

49.1%

easy

49

67.1%

easy

50

48.0%

easy

51

28.8%

Med.

52

16.7%

hard

53

linked list
recursion
sorting
+4 more

80.1%

easy

54

linked list
linked list reversal
recursion
+2 more

31.4%

Med.

55

53.0%

Med.

56

51.7%

Med.

57

linked list
doubly linked list
recursion
+2 more

22.9%

Med.

58

stack
string
depth-first search
+1 more

30.1%

easy

59

85.1%

easy

60

46.7%

Med.

61

array
stack
two pointers
+3 more

31.5%

easy

62

69.7%

easy

63

25.2%

Med.

64

linked list
linked list reversal
recursion
+1 more

41.9%

easy

65

58.6%

easy

66

stack
monotonic stack
array
+1 more

55.3%

easy

67

monotonic stack
array
stack

54.8%

easy

68

37.0%

Med.

69

monotonic stack
array
stack
+1 more

67.6%

Med.

70

greedy algorithm
stack
string
+1 more

12.6%

hard

71

55.3%

easy

72

0.0%

easy

73

hash map
counting
array
+1 more

61.4%

easy

74

hash map
counting
array
+1 more

0.0%

easy

75

39.7%

easy

76

0.0%

easy

77

string
array
hash map
+1 more

24.1%

easy

78

string
hash map
array
+1 more

0.0%

easy

79

string
hash map
counting
+1 more

56.7%

easy

80

hash map
string
counting

0.0%

easy

81

breadth-first search
binary tree
level order traversal
+1 more

73.4%

easy

82

breadth-first search
binary tree
queue
+1 more

89.2%

easy

83

binary tree
breadth-first search
level order traversal
+3 more

64.0%

Med.

84

binary tree
breadth-first search
level order traversal
+1 more

82.0%

easy

85

tree breadth first search
binary tree
breadth-first search
+2 more

90.5%

Med.

86

breadth-first search
binary tree
level order traversal
+1 more

54.0%

Med.

87

binary tree
tree breadth first search
level order traversal
+2 more

56.9%

Med.

88

binary tree
breadth-first search
depth-first search
+1 more

21.5%

easy

89

breadth-first search
level order traversal
binary tree
+1 more

63.9%

easy

90

breadth-first search
binary tree
level order traversal
+1 more

78.1%

Med.

91

binary tree
breadth-first search
tree depth first search
+3 more

32.1%

Med.

92

breadth-first search
n-ary tree
level order traversal

92.5%

hard

93

breadth-first search
level order traversal
binary tree
+1 more

80.1%

Med.

94

binary tree
tree breadth first search
level order traversal
+1 more

76.3%

easy

95

binary tree
depth-first search
recursion
+1 more

38.3%

easy

96

binary tree
depth-first search
recursion
+2 more

56.9%

Med.

97

binary tree
recursion
depth-first search

69.0%

Med.

98

binary tree
recursion
depth-first search
+1 more

25.9%

Med.

99

binary tree
depth-first search
recursion
+2 more

24.5%

Med.

100

binary tree
tree depth first search
recursion
+1 more

59.2%

Med.

Companies

Google

Meta

Microsoft

Amazon

Oracle

Linkedin

Topics

recursion

109

array

108

sorting

65

string

56

breadth-first search

53

depth-first search

53

greedy algorithm

44

hash map

42

two pointers

42

binary tree

30

counting

29

backtracking

27

graph

27

dynamic programming

26
+39 more