Python Program to Print uncommon elements from two sorted arrays

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Given two sorted arrays of distinct elements, we need to print those elements from both arrays that are not common. The output should be printed in sorted order.
Examples :

Input : arr1[] = {10, 20, 30}
        arr2[] = {20, 25, 30, 40, 50}
Output : 10 25 40 50
We do not print 20 and 30 as these
elements are present in both arrays.

Input : arr1[] = {10, 20, 30}
        arr2[] = {40, 50}
Output : 10 20 30 40 50

Method 1:
The idea is based on the merge process of merge sort. We traverse both arrays and skip common elements.

Python3

# Python 3 program to find uncommon
# elements of two sorted arrays
 
 
def printUncommon(arr1, arr2, n1, n2):
 
    i = 0
    j = 0
    k = 0
    while (i < n1 and j < n2):
 
        # If not common, print smaller
        if (arr1[i] < arr2[j]):
            print(arr1[i], end=" ")
            i = i + 1
            k = k + 1
 
        elif (arr2[j] < arr1[i]):
            print(arr2[j], end=" ")
            k = k + 1
            j = j + 1
 
        # Skip common element
        else:
            i = i + 1
            j = j + 1
 
    # printing remaining elements
    while (i < n1):
        print(arr1[i], end=" ")
        i = i + 1
        k = k + 1
 
    while (j < n2):
        print(arr2[j], end=" ")
        j = j + 1
        k = k + 1
 
 
# Driver code
arr1 = [10, 20, 30]
arr2 = [20, 25, 30, 40, 50]
 
n1 = len(arr1)
n2 = len(arr2)
 
printUncommon(arr1, arr2, n1, n2)

Output

10 25 40 50

Time Complexity: O(n1 + n2), where n1 and n2 represents the size of the given two arrays.
Auxiliary Space: O(1), no extra space is required, so it is a constant.

Method 2: Using Counter() function

Python3

from collections import Counter
 
# Python 3 program to find uncommon
# elements of two sorted arrays
 
 
def printUncommon(arr1, arr2):
    frequency_arr1 = Counter(arr1)
    frequency_arr2 = Counter(arr2)
    result = []
 
    for key in frequency_arr1:
        if key not in frequency_arr2:
            result.append(key)
    for key in frequency_arr2:
        if key not in frequency_arr1:
            result.append(key)
 
    # Sorting the result
    result.sort()
 
    for i in result:
        print(i, end=' ')
 
 
# Driver code
arr1 = [10, 20, 30]
arr2 = [20, 25, 30, 40, 50]
 
printUncommon(arr1, arr2)

Output

10 25 40 50

Please refer complete article on Print uncommon elements from two sorted arrays for more details!

Time Complexity: O(n*logn), as sort() function is used.

Auxiliary Space : O(n), where n is length of result list.

Method 3: using operator.countOf() method

Python3

# Python 3 program to find uncommon
# elements of two sorted arrays
import operator as op
 
 
def printUncommon(arr1, arr2):
    result = []
 
    for key in arr1:
        if op.countOf(arr2, key) == 0:
            result.append(key)
    for key in arr2:
        if op.countOf(arr1, key) == 0:
            result.append(key)
 
    # Sorting the result
    result.sort()
 
    for i in result:
        print(i, end=' ')
 
 
# Driver code
arr1 = [10, 20, 30]
arr2 = [20, 25, 30, 40, 50]
 
printUncommon(arr1, arr2)