Contents
Two Pointers........................................................................................................................4
Shift Zeros to the End................................................................................................................................................. 4
Next Lexicographical Sequence..............................................................................................................................9
Hash Maps and Sets........................................................................................................16
Longest Chain of Consecutive Numbers.......................................................................................................... 16
Geometric Sequence Triplets................................................................................................................................20
Linked Lists........................................................................................................................27
Palindromic Linked List............................................................................................................................................27
Flatten a Multi-Level Linked List..........................................................................................................................31
Fast and Slow Pointers.................................................................................................. 36
Happy Number Time Complexity Analysis......................................................................................................36
Binary Search................................................................................................................... 39
Find the Median From Two Sorted Arrays.......................................................................................................39
Matrix Search.............................................................................................................................................................. 46
Local Maxima in Array..............................................................................................................................................52
Weighted Random Selection.................................................................................................................................58
Stacks..................................................................................................................................65
Repeated Removal of Adjacent Duplicates.....................................................................................................65
Implement a Queue Using Stacks........................................................................................................................68
Maximums of Sliding Window.............................................................................................................................. 74
Heaps.................................................................................................................................. 81
Sort a K-Sorted Array...............................................................................................................................................81
Trees.................................................................................................................................... 88
Binary Tree Symmetry............................................................................................................................................. 88
Binary Tree Columns................................................................................................................................................ 92
Kth Smallest Number in a Binary Search Tree................................................................................................97
Serialize and Deserialize a Binary Tree.......................................................................................................... 102
