leetcode

class Solution:
    def threeSumClosest(self, nums, target):
        nums.sort()
        x = 0
        length = len(nums)
        res = nums[1] + nums[0] + nums[2]
        if length == 3:
            return res
        while  x < length:
            a = nums[x]
            y = x+1
            z = length-1
            while y < z:
                b = nums[y]
                c = nums[z]
                Sum = a + b + c
                if abs(target - Sum) < abs(target - res):
                    res = Sum
                if Sum > target:
                    z -= 1
                elif Sum < target:
                    y += 1
                else:
                    res = target
                    return res
            x += 1
        return res