Problem Link

Description


Given an integer array nums of length n 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 1:

Input: nums = [-1,2,1,-4], target = 1
Output: 2
Explanation: The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).

Example 2:

Input: nums = [0,0,0], target = 1
Output: 0
Explanation: The sum that is closest to the target is 0. (0 + 0 + 0 = 0).

 

Constraints:

  • 3 <= nums.length <= 500
  • -1000 <= nums[i] <= 1000
  • -104 <= target <= 104

Solution


Python3

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