[LeetCode] 3Sum Closest

3Sum Closest

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.

    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).

Solution: Based on [LeetCode] 3SUM.
Complexity: O(n^2). Since 3SUM can be solved in O(n^2) time. 

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public class Solution { public int threeSumClosest(int[] nums, int target) { Arrays.sort(nums); int minDist = Integer.MAX_VALUE; int closest = target; for (int i = 0; i < nums.length - 2; i++) { int j = i + 1; int k = nums.length - 1; while (j < k) { int sum = nums[i] + nums[j] + nums[k]; int dist = Math.abs(sum - target); if (dist < minDist) { minDist = dist; closest = sum; } if (sum == target) { return target; } else if (sum < target) { j++; } else { k--; } } } return closest; } }