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Algorithms & data structures medium

How to Find Four Sum Quadruplets in Python (Sorted Demo)

Find all unique quadruplets in a sorted array that sum to a target, with duplicate skipping.

two-pointers sorting four-sum
Python 
def four_sum(nums, target):
    nums.sort()
    result = []
    n = len(nums)

    for i in range(n - 3):
        if i > 0 and nums[i] == nums[i - 1]:
            continue
        for j in range(i + 1, n - 2):
            if j > i + 1 and nums[j] == nums[j - 1]:
                continue
            left, right = j + 1…
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