Introduction
代写三个Python的简单算法作业。主要考察基本数据类型的使用，以及程序设计的思想。
Objectives
The objectives of this assignment are:
- To demonstrate the ability to implement algorithms using basic data structures and operations on them.
- To gain experience in designing an algorithm for a given problem description and implementing that algorithm in Python.
Task 1: Australian Idol 8 Marks
You are hired by Australian Idol to write a program to create a scoreboard for them. Each participant is judged by 5 different judges where each judge gives a score between 0 to 10. You are given an input file named raw scores.txt which contains 10 lines (one for each participant). Each line contains 6 strings separated by spaces. The first string in each line is the name of the participant. The remaining 5 strings record the scores given by the 5 judges to the participant. Below is an example showing scores for three participants Mark, Alice and Alan.
Mark 1 10 0 2 9
Alice 8 10 8 0 10
Alan 10 10 10 10 10
The final score of each participant is computed as follows. To handle potentially biased judges, the highest score and lowest score received for the participant are ignored and the average of remaining three scores is the final score. E.g., for Mark, the highest score 10 and the lowest score 0 are ignored and his final score is (1 + 2 + 9) / 3 = 4. Alice’s final score is (8 + 8 + 10) / 3 = 8.67 (ignoring lowest score 0 and one of the two 10 scores) and Alan’s final score is (10 + 10 + 10) / 3 = 10 (ignoring the lowest score 10 and the highest score 10). Note that the final score is rounded to two decimal points (e.g., Alice’s score is rounded to 8.67). You can use round() function https://docs.python.org/3/library/functions.html#round.
Your program should read the raw scores.txt file and compute the final score for each participant. The results must be stored in a table called “Scoreboard” that consists of two columns recording the names of the participants and their final scores. Your program must also print the final score for each participant. Below is a sample output for the above input.
Mark: 4
Alice: 8.67
Alan: 10
Important: Your program will be checked on an input file that will contain data different than the data provided in raw scores.txt file. Therefore, do not tweak your program to work only for the provided file (e.g., by manually computing scores). However, you can assume that the input file will contain exactly 10 participants and each participant will be judged by exactly 5 judges. You can also assume that the name of the input file will be the same, i.e., raw scores.txt.
Task 2: Palindromes 10 Marks
You are given a sequence of letters (all lowercase). Your goal is to rearrange the letters to form a palindrome. The palindrome must contain all the given letters. The palindrome does not need to be an English word, i.e., it is any sequence of letters that is the same when reversed. If there is more than one palindromes that can be formed using all of the given letters, your program must output the lexicographically smallest palindrome string (i.e., the palindrome that appears first in the alphabetical order https://en.wikipedia.org/wiki/Alphabetical_order). For example, if the input sequence of letters is x y x z y, then xyzyx and yxzxy both are palindrome strings formed using all the letters in the sequence. However, xyzyx is the lexicographically smallest. Thus, the output must be xyzyx. If no palindrome can be formed by the letters in the input sequence then you must output impossible. For example, if the input sequence is a l g o r i t h m, your program must output impossible.
Your program must read from the input file named letters.txt that contains a single line containing a sequence of letters separated by spaces. Below is a sample input file.
x y x z y
There may be up to 1000 letters in the input line. Your program must create a list containing all these letters. Then, the program must print the lexicographically smallest palindrome that can be formed by the letters in the list. If no palindrome can be formed using all these letters, your program must output impossible
Task 3: (Almost) Good Strings 12 Marks
Suppose you are given two strings named s1 and s2 (containing only lowercase letters). The string s1 is called a “good” string if it contains s2, i.e., s2 is a substring of s1. For example, if s1 is smart and s2 is art, then s1 is a good string because smart contains art. The string s1 is called “almost good” if it is not a “good” string but inserting one character into it would make it a “good” string. For example, if s1 is smart and s2 is mark, then s1 is not a good string because mark is not a substring of smart. But s1 is an “almost good” string because inserting the letter k in s1 (between r and t) makes it smarkt which is a “good” string because it contains mark. The string s1 is called a “bad” string if it is neither a “good” nor an “almost good” string.
You need to write two functions called isGood(s1, s2) and isAlmostGood(s1, s2) that return true if and only if s1 is “good” and “almost good”, respectively.
Your program must ask the user to enter two input strings: first input string will be s1 and the second input string will be s2. Both strings must be converted to lowercase letters. Then, the program must call the two functions to determine whether s1 is a “good”, “almost good” or “bad” string. The result must be printed.