三元组相加获得结果最接近target

3SumClosest

• 给定一个数组，选择三个元素相加，结果必须为所有三元组中最接近target的值，返回这个三元组的和。
• 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.

example 1

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).input: [-1, 2, 1, -4], 1output: 2

思路

1. 思路参照三元组相加获得target
2. 只需要将上述文章思路2中换成：第二次循环找到 三元组的和 最接近target的组合即可。

代码

class Solution(object):    def threeSumClosest(self, nums, target):        """        :type nums: List[int]        :type target: int        :rtype: int        """        nums.sort()        closest = nums[0] + nums[1] + nums[2]        for i in range(len(nums)):            j, k = i + 1, len(nums) - 1            while j < k:                value = nums[i] + nums[j] + nums[k]                closest = value if abs(target - value) < abs(target - closest) else closest                if value == target:                    return target                elif value > target:                    k -= 1                else:                    j += 1        return closest

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