Python Challenges: Find the single element in a list where every element appears three times except for one

Last update on December 21 2024 07:49:26 (UTC/GMT +8 hours)

Write a Python program to find the single element in a list where every element appears three times except for one.

Explanation:

Sample Solution:

Python Code:

def single_number(arr):
    ones, twos = 0, 0
    for x in arr:
        ones, twos = (ones ^ x) & ~twos, (ones & x) | (twos & ~x)
    assert twos == 0
    return ones
arr1 = [5, 3, 4, 3, 5, 5, 3]
arr2 = [-1, 1, 1, -1, -1, 1, 0]
print(single_number(arr1))
print(single_number(arr2))

Sample Output:

4                                                                        
0

Flowchart:

Python Code Editor:

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