Question

Python

DESCRIPTION

Write a program that will read an array of integers from a file and do the following:

●

Task 1: Revert the array in N/2 complexity time

(i.e., number of steps)

.

●

Task 2: Find the maximum and minimum element of the array.

INPUT OUTPUT

Read the array of integers from a file named “

inputHW1.txt

”. To do this, you can use code snippet

from the “

file.py

” file. This file is provided in

Canvas. Copy the “

read

” function from this file and

paste it to your program file. Then, if you call the read function like the following:

numbers = read()

# The following "read" function reads values from a file named "inputHW1.txt" and

returns the values in an array.

def read():

file = open("inputHW1.txt", "r")

line = file.readline()

values = []

for value in line.split(' '):

values.append(int(value))

return values

the integers will be read from file and loaded in the numbers array.

Now, print the reverted arra

y, minimum element and maximum element of the array.

For example, if the input array is: 1 4 9 11 8 3 2 5 10

the following will be printed on the screen:

Reverted array: 10 5 2 3 8 11 9 4 1

Maximum element: 11

Minimum element: 1

EXTRA CREDIT - 30%

Find the trend change points of the array. You will get

30% extra credit

for doing this task.

Trend

change points are those points where the array

changes its direction

and

goes from

increasing to decreasing order or decreasing to increasing order.

Note that, you have to find the trend change points of the input array, not the reverted array.

For example, if the input array is: 1 4 9 11 8 3 2 5 10

the following will be printed on the screen:

Trend change points: 11 8 5

Answer 1

Note:-Here trend points are [11,2] but you are taking trend points [11,8,5] from 1->4->9->11 it's increasing but after 11 it's decreasing 11->8 and 11->8->3->2 it's decreasing but after 2 it's increasing 2->5->10.....so here 11 and 2 are change points so I Write the code like this

Code:-

def read(): #function to take input array from file
file=open("inputHW1.txt","r") #open input file in read mode
line=file.readline() #read line from file
values=[] #declaring list
for value in line.split(' '): #splitting the elements separated by space
values.append(int(value)) #append values to list
return values #returning list

numbers=read() #calling function
revertedarray=[] #reverted array to store elements copy of numbers
for i in numbers: #for loop to store copy elements from numbers to reverted array
revertedarray.append(i)
  
##here the concept to reversing the array is swapping first&last second &last but one...........
for i in range(int(len(revertedarray)/2)): #for loop in Time Complexity O(n/2)
#swapping process
temp=revertedarray[i]
revertedarray[i]=revertedarray[len(revertedarray)-i-1]
revertedarray[len(revertedarray)-i-1]=temp
  
max=revertedarray[0] #take first element in list as max value initially
min=revertedarray[0] #take first element in list as min value initially
for i in revertedarray:
if(i>max): #to find max
max=i
if(i<min): #to find min
min=i

print("Reverted array: ",end='') #printing reverted array
print(revertedarray)
print("Maximum Element: ",end='') #printing max element
print(max)
print("Minimum Element: ",end='') #printing min element
print(min)

diff=[] #diff list to store difference values between adjacent elements like (numbers[1] and numbers[0])
for i in range(1,len(numbers)):
diff.append(numbers[i]-numbers[i-1]) #appending each difference to diff list
trend=[] #trend list to store trend points
for i in range(1,len(numbers)-1):
if (diff[i]*diff[i-1] <=0): #if this value is negative means the sequence is changing to increasing to decreasing or decreasing to increasing
trend.append(numbers[i]) #appending trend values to list
print("Trend Values: ",end='')
print(trend) #printing trend points

Code Screenshot:-

File:-

Output:-