CBSE Class 12 : Data Structures

Introduction to Data Structures

CBSE Class 12 : Searching

Creation And Traversal
What is Searching?
Linear/Sequential Search
Binary Search
Insertion Of Element
Deletion Of Element

What is sorting?
Bubble Sort
Selection Sort
Insertion Sort

Class 12: Data Structures Searching 6

Example:2
Write a python script to search an element with in a list using Binary Search.(Create a user defined list)
Sol:

```def binary_search(arr, x):
low = 0
high = len(arr) - 1
mid = 0

while low <= high:

mid = (high + low) // 2

# Check if x is present at mid
if arr[mid] < x:
low = mid + 1

# If x is greater, ignore left half
elif arr[mid] > x:
high = mid - 1

# If x is smaller, ignore right half
else:
return mid

# If we reach here, then the element was not present
return -1

#-- main --
# create a user defined list
arr=[]
while True:
a=int(input("Enter the element to add "))
arr.append(a)
ch=input("Like to cont (y/n) ")
if(ch=="y" or ch=="Y"):
continue;
else:
break

#to display the list
print(arr)
#to sort the elements of the list arr
arr.sort()
#condition for binary search is elements should be sorted
print("Sorted list")
print(arr)
x=int(input("Enter the element to search "))
# Function call
result = binary_search(arr, x)
if result != -1:
print("Element is present at index", str(result)," position = ",str(result+1))
else:
print("Element is not present in array") ```

Output:

```Enter the element to add 10
Like to cont (y/n) y
Enter the element to add 25
Like to cont (y/n) y
Enter the element to add 96
Like to cont (y/n) y
Enter the element to add 4
Like to cont (y/n) y
Enter the element to add 65
Like to cont (y/n) n
[10, 25, 96, 4, 65]
Sorted list
[4, 10, 25, 65, 96]
Enter the element to search 25
Element is present at index 2  position =  3```

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