threeSumClosest.java

import java.util.*;

class Solution {
    public int threeSumClosest(int[] nums, int target) {
        if (nums.length < 3) {
            return 0;
        }
        
        Arrays.sort(nums);
        int closest = nums[0] + nums[1] + nums[2];
        
        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];
                if (Math.abs(sum - target) < Math.abs(closest - target)) {
                    closest = sum;
                }
                if (sum < target) {
                    j++;
                } else {
                    k--;
                }
            }
        }
        
        return closest;
    }
    
    public static void main(String[] args) {
        Solution solution = new Solution();
        int[] nums = {-1, 2, 1, -4};
        int target = 2;
        int result = solution.threeSumClosest(nums, target);
        System.out.println(result);
    }
}