SE106 Exercise Class 7
Quiz
Homework 9
Lab 4
Review
Solution 1
A: Impossible
B: push 1, 2, 3, pop 3, 2, push 4, 5, pop 5, push 6, pop 6, 4, 1
C: Impossible
D: Impossible
Solution 1
C
Radix sort efficiency is O(d·n) for n keys which have d or fewer
digits.
In general d cannot be considered a constant.
Solution 3
Hint:
Use in-order traverse and reverse in-order traverse
simultaneously.
Use the stack to save the traverse route.
Solution 3
Homework 9
wxdwfc@sjtu.edu.cn
Problem’s problem
•
Not using a priority queue.(not so efficient)
•
Wrong in-output format
•
not using -1 to indicate that the node is not
reachable.
•
The first n means [0,n] inclusively.
Solution
Solution
Solution
Lab4
Lab4
• 迟交
• Trace07
• 压缩解压后文件不同
• 不是最优的Huffman-Tree
Lab4
• Huffman树如何存
• 保存映射关系
• 变长
• 定长
• 保存节点信息
• 直接读取得到树
• 保存出现次数
• 读取次数重建树
5130309006 汤劲戈
5130379005 殷国航
Review
L1：Template Structures
•
Shallow vs. Deep Copying
• Total template specialization
• Partially specialize a function template
• Generic Programming
• Parametric type
• Iterator
• Algorithm／Functor
TMP: Template metaprogramming
Effective C++ Item 48
L3：Smart Pointers
L4：Collection Classes
Vector
collection
Grid
Stack
ordering
Queue
Map
benefits
array
by index
fast; simple
Vector
by insertion, by
index
by index, 2D
LIFO
FIFO
sorted order
unpredictable
sorted order
unpredictable
random access; fast
to modify at end
great for 2D data
simple; fast
simple; fast
sorted; pretty fast
very fast
sorted; pretty fast
very fast
Grid
Stack
Queue
Set
HashSet
Map
HashMap
Set
weaknesses
little functionality;
cannot resize
slow to modify in
middle/front
must be rectangular
little functionality
little functionality
must be comparable
unordered
must be comparable
unordered
L5-6： Recursion
• Recursive Strategies
• Recursive Backtracking
• Recursion VS Iteration
• Tail-recursion
L7： Sorting and Efficiency
L8： Maps and Hashing
Let λ = n / m (load factor)
Unsuccessful
Search
Chaining
1+α
Open
Addressing
( assuming
uniform hashing )
1 / (1 – α)
Successful
Search
1+α
(1 + average
number before
element in chain)
L9-10： Expression Tree and
Parsing Strategies
L11： BST-Binary Search Trees
If you process the current node before either recursive call,
the result is a preorder traversal.
If you process the current node after the recursive call on
the left subtree but before the recursive call on the right
subtree, the result is an inorder traversal. In the case of
the simple BST implementation that uses strings as keys,
the keys will appear in lexicographic order.
If you process the current node after completing both
recursive calls, the result is a postorder traversal.
Postorder traversals are particularly useful if you are
trying to free all the nodes in a tree.
L12-13： AVL Tree
L14-15： Red-Black Tree
L16： Huffman Coding
L16： MinHeap and HeapSort
L17： Splay Trees
L18-19： Graphs
Dijkstra’s Algorithm
Minimum Spanning Tree
L20： B Tree/B+ Tree
L21： General Tree and Forest
L22： Sets
Merry Xmas！