Python Challenges: Find the single number in a list that doesn't occur twice

Python Challenges - 1: Exercise-12 with Solution

Write a Python program to find the single number in a list that doesn't occur twice.

Explanation:

Sample Solution:

Python Code:

def single_number(arr):
    result = 0
    for i in arr:
        result ^= i
    return result

arr1 = [5, 3, 4, 3, 4]
arr2 = [3, 2, 5, 2, 1, 5, 3]

print(single_number(arr1))
print(single_number(arr2))

Sample Output:

5                                                                                                             
1

Flowchart:

Python Code Editor:

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