[LC] 16. 3Sum Closest

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).

class Solution {
    public int threeSumClosest(int[] nums, int target) {
        int globalMin = Integer.MAX_VALUE;
        int res = globalMin;
        if (nums == null || nums.length == 0) {
            return res;
        }
        Arrays.sort(nums);
        for (int i = 0; i < nums.length - 2; i++) {
            // skip i as well
            if (i > 0 && nums[i - 1] == nums[i]) {
                continue;
            }
            int j = i + 1, k = nums.length - 1;
            // j and k cannot meet since may add the same number twice
            while (j < k) {
                int sum = nums[i] + nums[j] + nums[k];
                if (sum < target) {
                    if (target - sum < globalMin) {
                        globalMin = target - sum;
                        res = sum;
                    }
                    j+=1;
                } else {
                    if (sum - target < globalMin) {
                        globalMin = sum - target;
                        res = sum;
                    }
                    k-=1;
                }
            }
        }
        return res; 
    }
}