Basic4.py

# Write a Python program to identify unique triplets whose three elements sum to zero from an array of n integers.
def three_sum(nums):
    result = []
    nums.sort()
    for i in range(len(nums)-2):
        if i>0 and nums[i] == nums[i-1]:
            continue
        l,r=i+1,len(nums)-1
        while l<r:
            s = nums[i]+nums[l]+nums[r]
            if s>0:
                r -= 1
            elif s<0:
                l += 1
            else:
            # found three sum
              result.append((nums[i],nums[l],nums[r]))
            # remove duplicates
              while l<r and nums[l] == nums[l+1]:
                l+=1
                while l<r and nums[r] == nums[r-1]:
                    r -= 1
                    l += 1
                    r -= 1
                return result

x = [1,-6,4,2,-1,2,0,-2,0]
print(three_sum(x))