Python Logic to Find All Unique Pairs in an Array

 Here's the Python logic for finding all unique pairs in an array that sum up to a target value.

Python Unique Pair

Problem

Write a Python function that finds all unique pairs in an array whose sum equals a target value. Avoid duplicates in the result. For example:

• Input: arr = [2, 4, 3, 5, 7, 8, 9], target = 9
• Output: [(2, 7), (4, 5)]

Hints

• Use a set for tracking seen numbers.
• Check for complements efficiently.

Example

def find_unique_pairs(arr, target):

    """

    Finds all unique pairs in the array that sum up to the target value.

    Parameters:

    arr (list): The input array of integers.

    target (int): The target sum value.

    Returns:

    list: A list of unique pairs that sum to the target value.

    """

    seen = set()

    pairs = set()

    for num in arr:

        complement = target - num

        if complement in seen:

            # Add the pair in sorted order to avoid duplicates

            pairs.add(tuple(sorted((num, complement))))

        seen.add(num)

    

    return list(pairs)

# Example usage

input_array = [2, 4, 3, 5, 7, 8, 9]

target_sum = 9

result = find_unique_pairs(input_array, target_sum)

print("Input Array:", input_array)

print("Target Sum:", target_sum)

print("Unique Pairs:", result)

Output:

For the input array [2, 4, 3, 5, 7, 8, 9] and target 9, the output will be:

Input Array: [2, 4, 3, 5, 7, 8, 9]
Target Sum: 9
Unique Pairs: [(4, 5), (2, 7)]

---

Explanation:

1. Tracking Seen Elements (seen Set):

   • Store numbers already processed in a set.
   • This helps in quickly checking if the complement (i.e., target - num) exists.

2. Avoiding Duplicate Pairs (pairs Set):

   • Pairs are stored in a set to automatically handle duplicate pairs.
   • Each pair is added as a sorted tuple to maintain consistency (e.g., (2, 7) and (7, 2) are treated as the same).

3. Conversion to List:

   • The result is converted to a list for output.