考前速记

Search

	Linear	Binary
Data	Unsorted OK	Must be sorted
Complexity	O(n)	O(log n)
Method	One by one	Divide & conquer

Sort

	Bubble	Insertion
Method	Swap adjacent	Insert into sorted part
Complexity	O(n²)	O(n²)

Stack vs Queue

	Stack	Queue
Principle	LIFO	FIFO
Add	Push	Enqueue
Remove	Pop	Dequeue
Pointer	StackPointer	Front / Rear

Linked List

Node: [Data][Pointer]
HeadPointer → Node1 → Node2 → NULL(-1)
FreePointer → available nodes

Insert: get from FreeList → update pointers Delete: bypass node → return to FreeList

Recursion — Checklist

• Base case exists?
• Recursive call moves toward base case?
• Call stack managed correctly?

Big O — Speed Ranking

$O(1) > O(\log n) > O(n) > O(n \log n) > O(n^2)$

Binary search → O(log n) ✓ Linear search → O(n) ✓ Bubble/Insertion sort → O(n²) ✓