# Python program to check if two lists have at least one common element

PythonServer Side ProgrammingProgramming

In this problem we use two user input list. Our task is to check that there is any common element or not. We use very simple traversing technique, traverse both the list and check the every element of first list and second list.

## Example

Input : A = [10, 20, 30, 50]
B = [90, 80, 30, 10, 3]
Output : FOUND
Input : A = [10, 20, 30, 50]
B = [100,200,300,500]


## Algorithm

commonelement(A,B)
/* A and B are two user input list */
Step 1: First use one third variable c which is display the result.
Step 2: Traverse both the list and compare every element of the first list with every element of the second list.
Step 3: If common element is found then c display FOUND otherwise display NOT FOUND.


## Example Code

# Python program to check
# if two lists have at-least
# one element common
# using traversal of list

def commonelement(A, B):

# traverse in the 1st list
for i in A:
# traverse in the 2nd list
for j in B:
# if one common
if i == j:
c="FOUND"
return c
return c

# Driver code
A=list()
B=list()
n1=int(input("Enter the size of the first List ::"))
print("Enter the Element of first List ::")
for i in range(int(n1)):
k=int(input(""))
A.append(k)
n2=int(input("Enter the size of the second List ::"))
print("Enter the Element of second List ::")
for i in range(int(n2)):
k=int(input(""))
B.append(k)

print("Display Result ::",commonelement(A, B))


## Output

Enter the size of the first List ::4
Enter the Element of first List ::
2
1
4
9
Enter the size of the second List ::5
Enter the Element of second List ::
9
90
4
89
67
Display Result :: FOUND

Enter the size of the first List ::4
Enter the Element of first List ::
67
89
45
23
Enter the size of the second List ::4
Enter the Element of second List ::
1
2
3
4