(Medium #16) 3Sum Closest

Problem

Given an array nums of n integers and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of the three integers. You may assume that each input would have exactly one solution.

Example:

Given array nums = [-1, 2, 1, -4], and target = 1.

The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).

My solution

class Solution:
    def threeSumClosest(self, nums: List[int], target: int) -> int:        
        nums.sort()
        closet = [nums[0], nums[1], nums[-1]]

        for i in range(len(nums)-2):
            choice_1 = nums[i]
            if i> 0 and choice_1 == nums[i-1]:
                continue

            start = i+1
            end = len(nums)-1
            
            while start < end:            
                choice_2 = nums[start]
                choice_3 = nums[end]                
                
                if choice_1+choice_2+choice_3-target < 0:
                    while start < end and nums[start] == nums[start+1]:
                        start += 1
                    start += 1    
                    if abs(choice_1+choice_2+choice_3-target) < abs(sum(closet)-target):
                        closet = [choice_1, choice_2, choice_3]
                elif choice_1+choice_2+choice_3-target > 0:
                    while start < end and nums[end] == nums[end-1]:
                        end -= 1
                    end -= 1
                    
                    if abs(choice_1+choice_2+choice_3-target) < abs(sum(closet)-target):
                        closet = [choice_1, choice_2, choice_3]
                else: # choice_1 + choice_2 + choice_3  == target:
                    closet = [choice_1, choice_2, choice_3]
                    return sum(closet)
                    

        return sum(closet)         

Runtime: 136ms, Memory: 13.8MB