leetcode 16. 3Sum Closest

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

For example, given array S = {-1 2 1 -4}, and target = 1.

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

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class Solution(object):
    def threeSumClosest(self,nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        nums.sort()
        min_target = float("inf")
        for i in range(len(nums)-2):
            l,r = i + 1,len(nums)-1
            while l < r:
                if nums[i] + nums[l] + nums[r] - target == 0:
                    return target
                if abs(nums[i] + nums[l] + nums[r] - target) <= abs(min_target - target):
                    min_target = nums[i] + nums[l] + nums[r]
                if nums[i] + nums[l] + nums[r] > target:
                    r -= 1
                elif nums[i] + nums[l] + nums[r] < target:
                    l += 1
                
        return min_target