# Python program to find common elements in three sorted arrays?

PythonProgrammingServer Side Programming

Here first we create 3 array which are user input unsorted array, then we sort all 3 unsorted arrays. The size of the arrays are n1,n2,n3.starting address of every array is 0.i=0,j=0,k=0,then traverse all the elements of three array and check the element of three arrays are same or not ,if same then print the element otherwise go the next element.

## Example

A = {1, 2, 3, 4, 5}
B = {2, 5, 12, 22, 7}
C = {1, 9, 2, 89, 80}


## Output

2


## Algorithm

commonele(A1,A2,A3,n1,n2,n3)
/* A1, A2, A3 are three integer sorted array and size1, size2, size3 are the sizes of the array.*/
Step 1: Initialize the starting indexes for A1, A2, A3.
i=0, j=0, k=0
Step 2:  iterate through three Arrays while arrays are nonempty.
While(i<size1 && j<size2 && k<size3)
Step 3: then check every value of A1,A2,A3.if the value are same then print otherwise move ahead in all arrays.
Step 4: End While


## Example Code

# To print common elements in three sorted arrays
def commonele (X, Y, Z, n1, n2, n3):
i, j, k = 0, 0, 0
print("Common elements are ::>")
while (i < n1 and j <n2 and k< n3):
if (X[i] == Y[j] and Y[j] == Z[k]):
print (X[i])
i += 1
j += 1
k += 1
elif X[i] < Y[j]:
i += 1
elif Y[j] < Z[k]:
j += 1
else:
k += 1
# Driver program
A=list()
B=list()
C=list()
n1=int(input("Enter the size of the First List ::"))
n2=int(input("Enter the size of the Second List ::"))
n3=int(input("Enter the size of the Third List ::"))
print("Enter the Element of First List ::")
for i in range(int(n1)):
k=int(input(""))
A.append(k)
print("Enter the Element of Second List ::")
for j in range(int(n2)):
k1=int(input(""))
B.append(k1)
print("Enter the Element of Third List ::")
for j in range(int(n3)):
k1=int(input(""))
C.append(k1)
X=sorted(A)
Y=sorted(B)
Z=sorted(C)
print("First Sorted List ::>",X)
print("Second Sorted List ::>",Y)
print("Third Sorted List ::>",Z)
commonele(X, Y, Z, n1, n2, n3)


## Output

Enter the size of the First List :: 4
Enter the size of the Second List :: 4
Enter the size of the Third List :: 5
Enter the Element of First List ::
23
12
45
8
Enter the Element of Second List ::
34
8
45
120
Enter the Element of Third List ::
2
4
8
45
1
First Sorted List ::> [8, 12, 23, 45]
Second Sorted List ::> [8, 34, 45, 120]
Third Sorted List ::> [1, 2, 4, 8, 45]
Common elements are ::>
8
45