Linear Search and Binary search

Aim:

To write a program to perform linear search and binary search using python programming.

Equipment’s required:

1. Hardware – PCs
2. Anaconda – Python 3.7 Installation / Moodle-Code Runner

Algorithm:

Linear Search:

1. Start from the leftmost element of array[] and compare k with each element of array[] one by one.
2. If k matches with an element in array[] , return the index.
3. If k doesn’t match with any of elements in array[], return -1 or element not found.

Binary Search:

1. Set two pointers low and high at the lowest and the highest positions respectively.
2. Find the middle element mid of the array ie. arr[(low + high)/2]
3. If x == mid, then return mid.Else, compare the element to be searched with m.
4. If x > mid, compare x with the middle element of the elements on the right side of mid. This is done by setting low to low = mid + 1.
5. Else, compare x with the middle element of the elements on the left side of mid. This is done by setting high to high = mid - 1.
6. Repeat steps 2 to 5 until low meets high

Program:

i) #Use a linear search method to match the item in a list.

  for i in range(0, n):
        if (array [i] == k):
            return i
    return -1

array = eval(input())
k =  eval(input())
n = len(array)
array.sort()
result = linearsearch(array, n, k)
if(result == -1):
    print(array)
    print("Element not found")
else:
    print(array)
    print("Element found at index: ", result)

ii) # Find the element in a list using Binary Search(Iterative Method).

for i in range(0, n):
    if (array [i] == k):
        return i
return -1

iii) # Find the element in a list using Binary Search (recursive Method).

    for i in range(0, n):
        if (array [i] == k):
            return i
    return -1

array = eval(input())
k =  eval(input())
n = len(array)
array.sort()
result = linearsearch(array, n, k)
if(result == -1):
    print(array)
    print("Element not found")
else:
    print(array)
    print("Element found at index: ", result)

Output:

Result

Thus the linear search and binary search algorithm is implemented using python programming.