Data structures and algorithms incorporated and Overview

Chapter One classical algorithm face questions

1.1 string matching problem

• ① has a string str1 = "How are you my bad bad is not good that I do not please you," and a sub-string str2 = "I'm so bad for you."
• ② now we need to determine whether str1 contains str2, if there is, please return to the first occurrence of the problem, if not, it returns -1.
• ③ requirements with the fastest speed to complete the match?

 

• Ideas ①: Matching violence
• For example: first with the "I" to match str1 str2 in, find the first str1 is "no", not match, and str1 continue in "good" match, not match, continue, to know matching " I "word, and then continue to take the" good "go and str1 in the" I "behind the character" does not "match, no match is found, continue to use str2 in the" I "go and str1 is" ​​no "match and then repeat this process, know all the characters and str1 str2 in a substring matching to.
• Question: match violence to solve if there are a lot of backtracking, a time to move one, if not match, then move up a judge, a waste of time.

 

• Ideas ②: KMP algorithm (partial match table).

1.2 Tower of Hanoi

• A disk ① all moved to column C column.
• ② The disk can not be enlarged small disk.
• ③ can only move a disc between three columns.

 

•  Ideas: Use divide and conquer algorithm.

1.3 Eight Queens problem

• International players busy Western Felix Bethel presented in 1848: placing eight queens on an 8 x 8 grid of chess, it can not be total with each other, namely: Any two queens can not be in the same line, the same the column or the same slash and asked how many there are in place. 92 kinds.

 

•  Ideas: backtracking algorithm.

1.4 horse riding board (Knights travel around)

• Horse riding board algorithm, also known as the Knights travel around the algorithm.
• A horse box will randomly on the international chess 8 * 8 chessboard, the horse moves in accordance with the rules of chess go (horse walking day). It requires each box is only entered once traveled all the 64 squares on the chessboard.

 

•  Ideas: the depth of the traversal algorithm of FIG optimization (DFS) + greedy optimization algorithm.

 

The importance of Chapter II data structures and algorithms

• Algorithm is the soul of the program, the program can be excellent when massive data computing, remains a high-speed computing.

• 一般来讲，程序会使用内存计算框架（如Spark）和缓存技术（如Redis）来优化程序，那么这些计算框架和缓存技术，其核心功能是什么？