0 Contents 0

Contents 

1 Rotate Array in Java 189 

2 Evaluate Reverse Polish Notation 150

3 Isomorphic Strings 21 

4 Word Ladder 23 

5 Word Ladder II 25 

6 Median of Two Sorted Arrays 29 

7 Kth Largest Element in an Array 31 

8 Wildcard Matching 33 

9 Regular Expression Matching in Java 35 

10 Merge Intervals 39 

11 Insert Interval 41 

12 Two Sum 43 

13 Two Sum II Input array is sorted 45 

14 Two Sum III Data structure design 47 

15 3Sum 49 

16 4Sum 53 

17 3Sum Closest 55 

18 String to Integer (atoi) 57 

19 Merge Sorted Array 59 

20 Valid Parentheses 61 

21 Longest Valid Parentheses 63 

22 Implement strStr() 65 

23 Minimum Size Subarray Sum 69 

24 Search Insert Position 73 

25 Longest Consecutive Sequence 75 

26 Valid Palindrome 77 

27 ZigZag Conversion 81 

28 Add Binary 83 

29 Length of Last Word 85 

30 Triangle 87 

31 Contains Duplicate 89 

32 Contains Duplicate II 91 

33 Contains Duplicate III 93 

34 Remove Duplicates from Sorted Array 95 

35 Remove Duplicates from Sorted Array II 99 

36 Longest Substring Without Repeating Characters 103 

37 Longest Substring Which Contains 2 Unique Characters 105 

38 Substring with Concatenation of All Words 109 

39 Minimum Window Substring 111 

40 Reverse Words in a String 113 

41 Find Minimum in Rotated Sorted Array 115 

42 Find Minimum in Rotated Sorted Array II 117 

43 Search in Rotated Sorted Array 119 

44 Search in Rotated Sorted Array II 121 

45 Min Stack 123 

46 Majority Element 125 

47 Majority Element II 127 

48 Remove Element 129 

49 Largest Rectangle in Histogram 131 

50 Longest Common Prefix 133 

51 Largest Number 135 

52 Simplify Path 137 

53 Compare Version Numbers 139 

54 Gas Station 141 

55 Pascal’s Triangle 143 

56 Pascal’s Triangle II 145 

57 Container With Most Water 147 

58 Candy 149 

59 Trapping Rain Water 151 

60 Count and Say 153 

61 Search for a Range 155 

62 Basic Calculator 157 

63 Group Anagrams 159 

64 Shortest Palindrome 161

65 Rectangle Area 163 

66 Summary Ranges 165 

67 Increasing Triplet Subsequence 167 

68 Get Target Number Using Number List and Arithmetic Operations 169 

69 Reverse Vowels of a String 171 

70 Flip Game 173 

71 Flip Game II 175 

72 Move Zeroes 177 

73 Valid Anagram 179 

74 Group Shifted Strings 181 

75 Top K Frequent Elements 183 

76 Find Peak Element 185 

77 Word Pattern 187 

78 Set Matrix Zeroes 189 

79 Spiral Matrix 193 

80 Spiral Matrix II 197 

81 Search a 2D Matrix 199 

82 Search a 2D Matrix II 201 

83 Rotate Image 205 

84 Valid Sudoku 207 

85 Minimum Path Sum 209 

86 Unique Paths 211 

87 Unique Paths II 213 

88 Number of Islands 215 

89 Number of Islands II 217 

90 Surrounded Regions 219

91 Maximal Rectangle 223 

92 Maximal Square 225 

93 Word Search 227 

94 Word Search II 229 

95 Integer Break 233 

96 Range Sum Query 2D Immutable 235 

97 Longest Increasing Path in a Matrix 237 

98 Implement a Stack Using an Array in Java 239 

99 Add Two Numbers 243 

100 Reorder List 245 

101 Linked List Cycle 251 

102 Copy List with Random Pointer 253 

103 Merge Two Sorted Lists 257 

104 Odd Even Linked List 259 

105 Remove Duplicates from Sorted List 261 

106 Remove Duplicates from Sorted List II 263 

107 Partition List 265 

108 LRU Cache 267 

109 Intersection of Two Linked Lists 271 

110 Remove Linked List Elements 273 

111 Swap Nodes in Pairs 275 

112 Reverse Linked List 277 

113 Reverse Linked List II 279 

114 Remove Nth Node From End of List 281 

115 Implement Stack using Queues 283 

116 Implement Queue using Stacks 285 

117 Palindrome Linked List 287 

118 Implement a Queue using an Array in Java 289 

119 Delete Node in a Linked List 291 

120 Moving Average from Data Stream 293