LeetCode16. 3Sum Closest（思路及python解法）

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).

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找到三个数的和，使这个和距离target距离最近。

思路和3sum差不多，只不过需要记录一下最短距离即可。

还是先将数组排序，然后利用两个指针去遍历数组。多了一步记录距离的过程，注意使用abs()

class Solution:
    def threeSumClosest(self, nums: List[int], target: int) -> int:
        nums.sort()
        closest=float('inf')
        
        for i in range(len(nums)):
            if i!=0 and nums[i]==nums[i-1]:continue
            l, r=i+1,len(nums)-1
            
            while l<r:
                sumx=nums[i]+nums[l]+nums[r]
                if sumx == target:
                    return target
                if abs(sumx-target)<abs(closest-target):
                    closest=sumx
                if sumx<target:
                    l+=1
                else:
                    r-=1
                    
        return closest

 

来源：CSDN

作者：船桥

链接：https://blog.csdn.net/AIpush/article/details/103986591