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Python Code Samples

Medium snippets you can copy, study, and run in the browser editor.

2 matches
Algorithms & data structures medium

Find the Majority Element in Python with Boyer-Moore Vote

Use Boyer-Moore majority vote to find the element appearing more than n/2 times in an array in O(n) time and O(1) space.

boyer-moore majority-element array
Python
def majority_element(nums):
    candidate = None
    count = 0

    for num in nums:
        if count == 0:
            candidate = num
        count += 1 if num == candidate else -1

    return candidate

if __name__ == "__main__":
    nums = [2, 2, 1, 1, 1, 2, 2]
    result = majority_element(nums)
    print(f"Major…
14 0 Open
Data pipelines & processing medium

Pivot long to wide transformation dict

Transform a list of dictionaries from long format to wide format by pivoting on a key column and aggregating values, using pure Python.

pivot transformation data-cleaning
Python
def pivot_long_to_wide(rows, key_col, value_col, id_cols=None):
    """
    Convert long-format data (list of dicts) to wide format.
    
    Args:
        rows: List of dicts in long format
        key_col: Column name to pivot on (becomes new column headers)
        value_col: Column name whose values become the cel…
11 0 Open

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