16. 3Sum Closest

import sys
class Solution:
    def threeSumClosest(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: int
        """
        res = 0
        t = abs(sys.maxsize - target)

        nums.sort()
        for i in range(0, len(nums)-2):

            l = i + 1
            r = len(nums) - 1

            while l < r:
                _sum = nums[i] + nums[l] + nums[r]

                diff = abs(_sum - target)
                if diff < t:
                    t = diff
                    res = _sum

                if _sum < target:
                    l = l + 1
                else:
                    r = r - 1

        return res