DSL/assignment-11.py

# List to store roll numbers of students that attended the program
programRoll=[]
attendees=int(input("Enter the number of students attending the program:\t"))

# Function to take input for roll numbers in list
def attendInput():
	for i in range(attendees):
		roll=int(input(f"Enter roll number for student {i+1}:\t"))
		programRoll.append(roll)
	print(f"Roll numbers of {attendees} students that attended the program are:\t {programRoll}")

# Linear search
def linearSearch(roll_list, roll_search):
	for i in roll_list:
		if i==roll_search:
		    return 1

# Sentinel search
def sentinelSearch(roll_list, roll_search, n):
    end=roll_list[n-1]
    roll_list[n-1]=roll_search
    i=0
    while (roll_list[i] != roll_search):
        i+=1
    roll_list[n-1]=end
    if ((i<n-1) or (roll_search==roll_list[n-1])):
        return 1
    else:
        return -1

def binarySearch(arr, target):
    arr.sort()
    # Binary search on the sorted list
    low, high = 0, len(arr) - 1
    while low <= high:
        mid = (low + high) // 2
        mid_element = arr[mid]

        if mid_element == target:
            return mid  # Target element found, return its index
        elif mid_element < target:
            low = mid + 1  # Target is in the right half
        else:
            high = mid - 1  # Target is in the left half

    return -1  # Target element not found in the list

'''
# DOESN'T WORK THIS ONE
# Binary search
def binarySearch(roll_list, roll_search, begin, n):
    if begin>n:
        return -1
    mid=(begin+n)//2
    if roll_search==roll_list[mid]:
        return mid
    if roll_search<roll_list[mid]:
        return binarySearch(roll_list, roll_search, begin, mid-1)
    else:
        return binarySearch(roll_list,roll_search,mid+1,n)
'''

# Fibonacci search
def fibonacciSearch(students_attend, search_element, n):
    students_attend.sort()
    fibMMm2 = 0
    fibMMm1 = 1
    fibM = fibMMm2 + fibMMm1
    while (fibM<n):
        fibMMm2=fibMMm1
        fibMMm1=fibM
        fibM=fibMMm2+fibMMm1
    offset=-1;
    while (fibM>1):
        i=min(offset+fibMMm2, n-1)
        if (students_attend[i]<search_element):
            fibM=fibMMm1
            fibMMm1=fibMMm2
            fibMMm2=fibM-fibMMm1
            offset=i
        elif (students_attend[i]>search_element):
            fibM=fibMMm2
            fibMMm1=fibMMm1-fibMMm2
            fibMMm2=fibM-fibMMm1
        else:
            return i
    if(fibMMm1 and students_attend[offset+1]==search_element):
        return offset+1;
    else:
        return -1

def main():

	# Input for marks and search roll
	attendInput()
	searchAttendee=int(input("\nEnter the roll number you want to search:\t"))
	
	# Options
	while True:
		print("\n----- CHOOSE SEARCH TYPE -----")
		print("1 -> Linear search")
		print("2 -> Sentinel search")
		print("3 -> Binary search")
		print("4 -> Fibonacci search")
		print("5 -> Exit")
		optn=int(input("\nChoose an option (1-5):\t"))
		
		if (optn==1):
			result=linearSearch(programRoll, searchAttendee)
			if (result==1):
			    print(f"\nRoll number {searchAttendee} attended the program.\n")
			else:
			    print(f"\nRoll number {searchAttendee} has either not been added to the list or was absent.\n")
		elif (optn==2):
			result=sentinelSearch(programRoll, searchAttendee, attendees)
			if (result==1):
			    print(f"\nRoll number {searchAttendee} attended the program.\n")
			else:
			    print(f"\nRoll number {searchAttendee} has either not been added to the list or was absent.\n")
		elif (optn==3):
			result=binarySearch(programRoll, searchAttendee)
			if (result==-1):
			    print(f"\nRoll number {searchAttendee} has either not been added to the list or was absent.\n")
			else:
			    print(f"\nRoll number {searchAttendee} attended the program.\n")
		elif (optn==4):
			result=fibonacciSearch(programRoll, searchAttendee, attendees)
			if (result==-1):
			    print(f"\nRoll number {searchAttendee} has either not been added to the list or was absent.\n")
			else:
			    print(f"\nRoll number {searchAttendee} attended the program.\n")
		elif (optn==5):
			print("\n## END OF CODE\n\n")
			quit()
		else:
			print("\nPlease choose a valid option (1-5)\n")
			main()

# Calling main function
main()