3Sum Closest

Description

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 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).

 

Constraints:

• 3 <= nums.length <= 10^3
• -10^3 <= nums[i] <= 10^3
• -10^4 <= target <= 10^4

Solution(javascript)

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number}
 */
const threeSumClosest = function (nums, target) {
  let diff = Infinity
  let result = 0
  nums.sort((a, b) => a - b)
  for (let i = 0; i < nums.length; i++) {
    let left = i + 1
    let right = nums.length - 1
    while (left < right) {
      const sum = nums[i] + nums[left] + nums[right]
      const currentDiff = sum - target
      if (currentDiff > 0) {
        right -= 1
      } else {
        left += 1
      }
      if (Math.abs(currentDiff) < diff) {
        result = sum
      }
      diff = Math.min(Math.abs(currentDiff), diff)
    }
  }
  return result
}