Week 9 Notes

# 

# Python Problem Solver

# Week 9 Example 1: Subbookkeeper 

#

N = int(input().strip())

line = input().strip()

newlist = []

answer = 0

for i in range(0,N):

    if line[i] == "?":

        if i == 0:

            newlist.append(line[i+1])

        else:

            newlist.append(line[i-1])

    else:

        newlist.append(line[i])

for i in range(0,N-1):

    if newlist[i] == newlist[i+1]:

        answer += 1

print(answer)

# 

# Python Problem Solver

# Week 9 Example 2: The Vigenere Cipher 1

#

original = input("Input the plain text: ").strip().upper()

key = int(input("Input the encryption key: ").strip())

cipher = ""

for c in original:

    asc = ord(c)

    asc += key

    if asc > 90:

        asc -= 26

    cipher += chr(asc)

print(f"The Caesar cipher of '{original}' is '{cipher}'.")

# 

# Python Problem Solver

# Week 9 Example 2: The Vigenere Cipher 2

#

original = input("Input the plain text: ").strip().upper()

key = input("Input the encryption key: ").strip().upper()

keylist = []

for k in key:

    keylist.append(ord(k) - 65)

keylist *= len(original)//len(key)+1

cipher = ""

for i in range(len(original)):

    asc = ord(original[i])

    asc += keylist[i]

    if asc > 90:

        asc -= 26

    cipher += chr(asc)

print(f"The Caesar cipher of '{original}' is '{cipher}'.")

Week 8 Assignments

 

Week 8 Notesz

import sys

sys.setrecursionlimit(1000000000)

#

# Solution Template for Robot Vacuum

# 

# Australian Informatics Olympiad 2021

# 

# This file is provided to assist with reading of input and writing of output 

# for the problem. You may modify this file however you wish, or

# you may choose not to use this file at all.

#

# K is the number of instructions.

K = 0

# instrs contains the sequence of instructions.

instrs = ""å

answer = 0

# Read the value of K and the sequence of instructions.

K = int(input().strip())

instrs = input().strip()

# TODO: This is where you should compute your solution. Store the fewest number

# of instructions you need to add to the end of the sequence into the variable

# answer.

x, y = 0, 0

for i in instrs:

    if i == "N":

        y += 1

    elif i == "E":

        x += 1

    elif i == "S":

        y -= 1

    else:

        x -= 1

answer = abs(x) + abs(y)

# Write the answer.

print(answer)

# 

# Python Problem Solver

# Week 8 Example 2: Archaeologist's Challenge

#

import math

thalf = 5730

c14 = float(input("Input the current Carbon-14 to Carbon-12 ratio: "))

age = int(-(thalf / math.log(2) * math.log(c14)))

print(f"The age of the artefact is around {age} years.")

# 

# Python Problem Solver

# Week 8 Example 3: How Security is Your Password

#

N = 52

L = 10

c = N**L

sec = c//1000000000

days = sec//86400

years = days//365

days -= years * 365

rsec = sec - (years * 365 + days) * 86400

hours = rsec//3600

minutes = (rsec - hours * 3600)//60

seconds = rsec - hours * 3600 - minutes * 60

print(f"The password will be cracked in {years} years, {days} days, {hours} hours, {minutes} moinutes and {seconds} seconds")

Week 7 Assignments

Week 7 Notes

# 

# Python Problem Solver

# Week 7 Example 1: YOLO

#

line = input()

# Split input into a list of words in list2

list1 = line.split()

# list2 is used for output

list2 = []

for word in list1:

    # For each word in list1, append its 1st character to the end of list2

    list2.append(word[0])

# Join all the "1st characters" into 1 string and conver to upper case

print("".join(list2).upper())

# 

# Python Problem Solver

# Week 7 Example 2: Optical Illusions

#

from turtle import *

speed(10)

def drawCircle(x, y, r, c):

    penup()

    pencolor(c)

    fillcolor(c)

    goto(x, y - r)

    pendown()

    begin_fill()

    circle(r)

    end_fill()

    penup()

    hideturtle()

# Pay attention to all the coordinates are calcuated

drawCircle(-50, 0, 30, "purple")

drawCircle(-150, 0, 50, "black")

drawCircle(-50, 100, 50, "black")

drawCircle(50, 0, 50, "black")

drawCircle(-50, -100, 50, "black")

drawCircle(250, 0, 30, "purple")

drawCircle(310, 0, 10, "black")

drawCircle(250, -60, 10, "black")

drawCircle(190, 0, 10, "black")

drawCircle(250, 60, 10, "black")

input()

# 

# Python Problem Solver

# Week 7 Example 3: Calculating Pi

#

N = int(input())

sum = 0

for n in range(1, N+1):

    sum += 1/(n*n)

answer = (sum * 6) ** .5

print(f"The {N}-th approximation of Pi is {answer}")

Week 6 Assignments

Week 6 Notes

# 
# Python Problem Solver
# Week 6 Example 1: World Population in 2025
#
year = 2025
population = 8_230_000_000
while population < 10_000_000_000:
    population *= 1.01
    year += 1
print(f"By year {year}, world population will be {int(population):,}")

import sys

sys.setrecursionlimit(1000000000)

#

# Solution Template for Buried Treasure

# 

# Australian Informatics Olympiad 2025

# 

# This file is provided to assist with reading of input and writing of output

# for the problem. You may modify this file however you wish, or

# you may choose not to use this file at all.

#

# N is the number of clues.

N = 0

# L is the number of locations.

L = 0

# A and B contain clues. Note that the lists start from 0, and so the first

# clue is (A[0], B[0]) and the last clue is (A[N-1], B[N-1]).

A = []

B = []

# Read the values of N, L, and the clues.

N, L = map(int, input().strip().split())

for i in range(0, N):

  input_vars = list(map(int, input().strip().split()))

  A.append(input_vars[0])

  B.append(input_vars[1])

# TODO: This is where you should compute your solution. Store the number of

# locations that are consistent with all N clues into the variable answer.

answer = 0

left = 1

right = L

for i in range(N):

    if A[i] > left:

        left = A[i]

    if B[i] < right:

        right = B[i]

if left <= right:

    answer = right - left + 1

# Write the answer.

print(answer)